Dell OptiPlex All-in-One Plus 7420 Desktop System Guide
Summary: This article provides information about how to set up and use your Dell OptiPlex All-in-One Plus 7420 Desktop. Learn how to run a hardware diagnostic test, download, and install drivers and more. Find troubleshooting resources to resolve common issues. ...
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Instructions
Technical specifications
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| Chipset |
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| Processor |
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| PCIe bus |
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| System Memory (RAM) |
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| Supported operating systems |
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Ports on the Dell OptiPlex All-in-One Plus 7420 Desktop
| Description | Values |
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| Audio ports |
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| Video ports |
NOTE: Depending on the graphics card that is installed on the computer, the available video ports may vary.
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| Network ports |
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| USB ports |
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| M.2 ports |
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- Connect the keyboard and mouse to the computer.
- Connect the Ethernet cable to the computer, or connect to a wireless network (if applicable).
- Connect the monitor using the VGA, DVI, HDMI, or DisplayPort cable provided with the monitor.
- Connect the power cable to the computer.
- Press the power button and turn on the computer.
- Follow the instructions on the screen to complete the setup procedure.
Figure 1: Animated illustration of setting up a desktop.
Running a hardware diagnostic test can help you identify hardware-related problems and provide you with troubleshooting steps to help resolve the issue.
To determine if your Dell computer is experiencing a hardware problem, it is recommended that you first run a hardware diagnostic test.
How to run a hardware diagnostic test using Dell SupportAssist?
If the computer can boot into the operating system, run the hardware diagnostic test using Dell SupportAssist.
NOTE: SupportAssist is available for Windows computers only. If SupportAssist is not available on your Dell computer, download and install the SupportAssist app.
- Click Start.
- Open SupportAssist.
- Click Start Now.
- The default test scans the computer for hardware failure.
How to run a pre-boot system assessment test?
If the computer cannot boot into the operating system, run the pre-boot system assessment test.
NOTE: Some diagnostic tests are interactive and require the user to respond. If no response is provided, the test results may be inaccurate.
- Restart the computer.
- At the Dell logo, tap the F12 key several times until the One-time Boot Menu appears.
- Use the arrow keys to select Diagnostics and press the Enter key.
- Follow the on-screen prompts and respond appropriately to complete the diagnostics.
- If the test passes, the hardware components are working correctly.
- If the test fails, make a note of the error code, validation code, and service tag, and then look up the error code.
How to Run a Preboot Diagnostics on a Dell Computer
Watch this video to learn how to use the integrated preboot diagnostics to identify hardware issues on your Dell computer.
Duration: 00:01:34 (hh:mm:ss)
Closed captions: Available in multiple languages. Click the CC icon, and then select the preferred language.
NOTE: Dell provides tested and validated drivers that are developed for Dell products. These drivers are provided for operating systems that Dell validates and supports for each product. Dell recommends downloading drivers for third-party devices from the device manufacturer's website.
Downloading drivers using SupportAssist
NOTE: SupportAssist is available for Windows computers only. If SupportAssist is not available on your Dell computer, download and install the SupportAssist app.
- Click Start and type
SupportAssist. - Click the SupportAssist app in the search results.
- In the SupportAssist window, click Start now.
- SupportAssist automatically scans your computer, checks for driver updates, downloads, and installs the latest drivers (if available).
- SupportAssist also runs other automated tasks such as scan hardware, tune performance, optimize the network, and so on.
Downloading drivers from Dell Support website
- Go to the Dell OptiPlex All-in-One Plus 7420 Desktop drivers page.
- Click Check for Updates to allow Dell to automatically find driver updates for you.
- Alternatively, click Find drivers to manually locate and download the drivers using:
- Keyword search box - Enter a keyword of the driver that you are looking for. For example, BIOS, Chipset, Audio, Video and so on.
- Operating System and Category filters - Select the operating system that is installed on the Dell computer and choose a driver category.
- Click the Download button next to the driver of your choice and save the file. Click Show All to see the remaining drivers.
- Using File Explorer (also known as Windows Explorer), browse to the location where the downloaded file was saved.
- Double-click the downloaded driver installation file and follow the on-screen instructions to complete the installation process.
- Repeat steps 5 to 7 for other drivers (if required).
- After the driver installation is complete, restart the computer.
Dell Digital Locker
The Dell Digital Locker allows you to view and manage your products, software, subscriptions, and licensing information in one location. You can:
- Download purchased software
- Access licensed software products
- Download updates and patches
- Manage user and product groups
- View software license entitlements
- Manage warranty subscriptions
To access Dell Digital Locker, go to https://www.dell.com/support/software. For more information, see the frequently asked questions about Dell Digital Locker.
Dell Digital Delivery
Dell Digital Delivery is an easy and new way to buy software when you purchase a Dell computer. You can automatically download and install available software titles on select computers.
To learn more, go to the Dell Digital Delivery website.
Operating System Recovery Image
Do you want to reinstall the operating system due to a computer crash, hard drive replacement, or other serious software problem with your Dell computer?
The Dell OS Recovery tool provides an interface to quickly download and create a bootable USB drive to reinstall the operating system. You can download the operating system recovery image that is customized for your Dell computer.
NOTE: The recovery image is available for the original operating system that was shipped with the Dell computer.
To download the Dell OS Recovery Tool, go to https://www.dell.com/support/home/drivers/osiso/recoverytool.
Third-party apps
Need help with downloading and installing third-party apps such as Microsoft Teams, Skype, Adobe Reader and more?
You can download and install third-party apps from the Microsoft Store or the software manufacturer's website.
If your computer cannot boot to the operating system even after repeated attempts, it automatically starts SupportAssist OS Recovery.
SupportAssist OS Recovery is a standalone tool that is preinstalled in all Dell computers that are shipped with the Windows operating system. It consists of tools to diagnose and troubleshoot issues that may occur before your computer boots to the operating system. It enables you to diagnose hardware issues, repair your computer, back up your files, or restore your computer to its factory state.
CAUTION: Dell recommends backing up your data before you begin the recovery or reset process.
CAUTION: Formatting the hard drive of your computer deletes the SupportAssist OS Recovery environment.
Manually start SupportAssist OS Recovery
NOTE: If the SupportAssist OS Recovery user interface is displayed for the first time, click APPROVE to accept the privacy policy. A walkthrough option is also displayed. Click START WALKTHROUGH to learn about various options available in the tool, or click SKIP to skip the walkthrough process.
- Turn on or restart the computer.
- At the Dell logo, press the F12 key several times to access the One Time Boot Menu.
NOTE: If the computer boots to the operating system, wait until you see the Windows desktop, restart the computer, and try again.
- Select SupportAssist OS Recovery, and then press Enter.
- Follow the instructions on the screen to scan, repair, backup files or reset the computer.
Learn more about how to Restore your system using SupportAssist OS Recovery.
Bluescreen or STOP Errors
There are many reasons that a computer does not start up. Does not boot into the Windows operating system or displays a full screen or STOP error when operating.
Learn How to Troubleshoot Blue Screen or STOP Error Code on a Dell Computer.
Bluetooth
Are you experiencing the following Bluetooth issues on your Dell computer?
- Cannot listen to music on a Bluetooth headset.
- Cannot transfer files to Bluetooth-enabled devices such as mobile phones or other computers.
Follow the suggested quick steps to resolve Bluetooth-related issues.
Fan and thermals
Are you experiencing the following thermal issues on your Dell computer?
- The computer fans are running too fast or making a loud noise.
- Computer restarts or shuts down intermittently.
- Getting an error message that is related to fan, temperature, or heat sink.
- Computer performance reduces unexpectedly.
Follow the suggested quick steps to resolve fan-related issues on your Dell desktop.
Keyboard
Are you experiencing the following keyboard issues on your Dell computer?
- One or more keys are not responding.
- Keys are responding slowly.
- Key presses are typing characters intermittently or typing incorrect characters.
Follow the suggested quick steps to resolve keyboard-related issues.
Microphone
Are you experiencing the following sound or audio recording issues on your Dell computer?
- Other users cannot hear you on Microsoft Teams, Skype, or Zoom call.
- Sound or audio from the microphone is muffled, distorted, crackling, or popping, choppy, or intermittent.
- Microphone volume is too low or no volume.
Follow the suggested quick steps to microphone-related issues.
Monitors and screens
Are you experiencing the following display issues on your Dell computer?
- The screen does not turn on or the screen is blank or black.
- The image on the screen is fuzzy, blurry, distorted, or faded.
- There are horizontal or vertical lines on the screen.
Follow the suggested quick steps to resolve display-related issues on a Dell computer.
Mouse
Are you experiencing the following mouse or touchpad issues on your Dell computer?
- Mouse cursor moves too slowly or erratically.
- Mouse buttons are not responding.
- Mouse cursor disappears.
Follow the suggested quick steps to resolve mouse or touchpad-related issues.
Slow Performance
Are you experiencing the following performance issues on your Dell computer?
- The computer takes a long time to boot.
- Apps are loading slowly or stops responding.
- Browsers and other apps stop responding.
Speakers or Headphones
Are you experiencing the following sound or audio playback issues on your Dell computer?
- No sound coming from the speakers or headphones.
- Sound or audio is muffled, distorted, crackling, or popping, choppy, or intermittent.
- Volume is too low or no volume.
Follow the suggested quick steps to resolve speaker or headphone-related issues.
Touchscreen
Are you experiencing the following touchscreen issues on your Dell computer?
- Touchscreen does not work.
- The touchscreen responds inaccurately or stops responding.
Learn How to Troubleshoot Touch Screen or Touch Panel Issues.
Webcam
Are you experiencing the following webcam issues on your Dell computer?
- Webcam does not work.
- Webcam is not detected in apps such as Microsoft Teams, Skype, or Zoom.
- Webcam image is fuzzy, dim, or grainy.
Follow the suggested quick steps to resolve webcam-related issues.
Wired networking
Are you experiencing the following wired network (Ethernet) issues on your Dell computer?
- No Internet using a wired network or Ethernet connection.
- Slow connection.
Follow the suggested quick steps to resolve wired networking issues.
Wireless networking
Are you experiencing the following Wi-Fi issues on your Dell computer?
- Cannot connect to nearby Wi-Fi networks.
- Slow connection.
- Wi-Fi connection is intermittent or connection drops.
- No Internet using Wi-Fi.
Follow the suggested quick steps to resolve wireless networking issues.
Learn how to view or download the Manuals and Documentation for your Dell Product.
- Dell OptiPlex All-in-One Plus 7420 Desktop - User’s Guide
- Dell OptiPlex All-in-One Plus 7420 Desktop - Service Manual
- Dell OptiPlex All-in-One Plus 7420 Desktop - Setup and Specifications
Additional Information
Frequently Asked Questions
For more information, click to expand a section below.
Computer maintenance means keeping your desktop or all-in-one in a good condition both internally and externally. A well-maintained computer looks good, lasts longer, and performs reliably. Regular maintenance helps increase the lifespan of the computer and protect the privacy and security of your data.
See our Dell Desktop Best Practices for Care, Use, and Handling and General Maintenance Guidelines For a Dell Computer.
If your Dell computer does not turn on or boot into the operating system, it is recommended that you first perform a hard reset. Performing a hard reset fixes many problems and also drains residual power that may be causing the problem.
- Turn off the computer.
- Disconnect the power cable.
- Disconnect all devices such as USB drives, printers, webcams, and media cards (SD/xD), except keyboard and mouse.
- Press and hold the power button for 15-20 seconds to drain residual power.
- Connect the power cable and turn on the computer.
Running a hardware diagnostic test can help you identify hardware-related problems and provide you with troubleshooting steps to help resolve the issue.
The diagnostics section of this article provides step-by-step instructions on how to run the SupportAssist or preboot diagnostic tests on your Dell OptiPlex All-in-One Plus 7420.
WARNING: Dell recommends disconnecting any external devices like external hard disk drives, printers, scanners before updating the BIOS.
NOTE: Learn more about Dell BIOS Updates.
NOTE: You must be logged in as an administrator to install the latest BIOS on your Dell computer.
Before you begin, temporarily suspend BitLocker protection in Windows. Learn How to Enable or Disable BitLocker with TPM in Windows. BitLocker protection resumes automatically when the computer is restarted.
- Go to the Dell OptiPlex All-in-One Plus 7420 drivers page.
- Select the Operating System that is installed on the computer.
- Under Category, select BIOS.
- Locate the latest System BIOS.
- Click Download and save the file to your computer.
- Using File Explorer (also known as Windows Explorer), browse to the location where the downloaded file was saved.
- Double-click the downloaded BIOS setup file and follow the on-screen instructions to complete the installation process.
- The computer restarts and completes the BIOS update process.
The troubleshooting section of this article provides self-help resources to troubleshoot and resolve common issues on your Dell OptiPlex All-in-One Plus 7420.
If the topic that you are looking for is not available, use the search bar at the top of this page.
Affected Products
OptiPlex All-in-One Plus 7420Article Properties
Article Number: 000223265
Article Type: How To
Last Modified: 27 Mar 2024
Version: 1
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