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Computer Won't POST: POST Error on Laptops and Desktops

When your Dell computer can’t complete the POST (Power-On Self-Test), it might freeze at the Dell logo, show no display, or seem inactive even when powered on. You might hear beeps or see blinking LED lights. These issues are often due to hardware or configuration problems.

What is POST?

POST stands for Power-On Self-Test. It’s like a quick check-up your computer does every time you turn it on to make sure everything is working properly.

How does POST work?

  1. Power On: When you press the power button, your computer wakes up and starts the POST process.
  2. Hardware Check: The computer checks all its important components like the CPU (processor), RAM (memory), and graphics card (for the display).
  3. Beep or LED Codes: If something is wrong, the computer might make a series of beeps or flashes LED status lights. These beeps or flashing LEDs are like a secret code that tells you what the problem is.
  4. Display Check: The computer checks if the monitor is connected and working.
  5. BIOS Screen: If everything is okay, you’ll see the Dell logo. This means the computer is ready to start loading the operating system (like Windows).

Before you begin

It can be hard to tell if your computer has a power, POST, boot, or display issue when you turn it on. We can help you figure it out. Once you know the problem, follow the links for detailed troubleshooting steps:

  • No Power: Does your computer not turn on at all? No lights, no fans, no sounds? This means there’s a power issue. Check out our troubleshooting guide if your computer won’t turn on.
  • No POST: Does your computer turn on, but nothing shows on the screen? Does the caps lock key not light up when pressed? Do you hear beeps or see blinking lights? Is the computer stuck at the Dell logo? These signs mean there’s a POST problem. Follow the troubleshooting steps provided in this article.
  • No Boot: Does your computer pass POST, but the operating system doesn’t load? Do you see an error message like “No Bootable Device Found” or a blank screen with a blinking cursor? Does the Windows login screen appear, but you can’t log in, or do you see an error message? Use our troubleshooting guide if your computer can’t boot into Windows.
  • No Video: Does your computer seem to be running (fans spin, status LEDs on), but nothing shows on the monitor? Is the screen blank? Follow our display troubleshooting guide to fix common display or video issues.

Fix No POST Startup Failure

Video about how to troubleshoot No POST or startup failure issue

Watch this video to troubleshoot and fix startup issues on your Dell computer.

If your Dell laptop or desktop computer is experiencing a No POST (Power-On Self-Test) or does not startup, follow these detailed step-by-step instructions to troubleshoot and resolve the problem.

Step 1: Check Power Supply

  • Ensure Power Connection: Verify that the power cable is securely connected to both the computer and the power outlet.
  • Test Power Outlet: Plug another device into the same outlet to ensure it’s working.
  • Check Power Adapter: For laptops, ensure the power adapter is connected properly and the LED indicator is on. Ensure to use the Dell provided or Dell-approved power adapter.
  • Turn On the Computer: Press the power button to see if the issue is resolved.

Step 2: Perform a Hard Reset

  • Turn Off the Computer: Press and hold the power button until the computer shuts down.
  • Disconnect Power: Unplug the power cable (and battery for laptops with a removable battery).
  • Drain Residual Power: Press and hold the power button for 15-20 seconds.
  • Reconnect Power: Plug the power cable back in (and reinsert the battery for laptops).
  • Turn On the Computer: Press the power button to see if the issue is resolved.

Step 3: Check External Devices

  • Disconnect All Peripherals: Remove all external devices such as docking station, USB drives, printers, and external hard drives (except keyboard and mouse).
  • Restart the Computer: Turn on the computer to see if it boots without the peripherals to see if the issue is resolved. If it does, connect one device at a time to find out which one is causing the problem.

Step 4: Check for Beep Codes or LED Codes

Beep codes or LED codes are like a computer's way of telling you something is wrong. Think of it like this: the computer makes a series of beeps or flashes the LED status lights. Different patterns of beeps or LEDs flashing (long, short, or a mix) mean different things that helps you figure out what the problem might be.

  • Observe Error Codes: Listen for any beep codes and observe any LED codes that indicate hardware issues.
  • Refer to User Manual: Check your computer’s user manual for the meanings of beep codes or LED codes and follow the corresponding troubleshooting steps.

Step 5: Check Display Connections

These steps will help you check if the display connections are causing the problem.

  • External Monitor (desktops or laptops): Make sure the monitor is securely connected to the computer. Check that the monitor is turned on and set the correct input source.
  • Internal Display (laptops): Check the laptop screen to see if anything shows up. Try using the function keys (fn + F8) to switch between display modes.

Step 6: Check System Board (laptops)

On supported Dell laptops run the system board built-in self-test diagnostics to identify a potential hardware failure with the system board.

  • Turn Off the Computer: Before initiating M-BIST, ensure that the computer is in a power-off state.
  • Start M-BIST: Press and hold the M key and the power button to initiate M-BIST.
  • Battery Status LED:
    • OFF indicates no fault was detected with the system board, skip to the next step.
    • Amber LED indicates a problem with the system board and the LED flashes an error code for 30 seconds. Refer to the user manual to identify the possible problem and contact Dell Technical Support for repair options based on your device’s warranty status.

Frequently Asked Questions

1. How can I identify beep codes on my Dell computer?

  • Turn On the Computer: Listen for any beep codes.
  • Count the Beeps: Note the number and pattern of beeps.
  • Refer to User Manual: Check the user manual of your computer for the meanings of the beep codes.

2. What do blinking LED codes mean on my Dell computer?

  • Turn On the Computer: Observe any blinking LED lights (power button, HDD activity, battery status lights).
  • Count the Blinks: Note the number and pattern of blinks.
  • Refer to User Manual: Check the user manual of your computer for the meanings of the LED codes.

3. How do I perform a hard reset of my Dell computer?

  • Turn Off the Computer: Press and hold the power button until the computer shuts down.
  • Disconnect Power: Unplug the power cable (and battery for laptops with removable batteries).
  • Drain Residual Power: Press and hold the power button for 15-20 seconds.
  • Reconnect Power: Plug the power cable back in (and reinsert the battery for laptops).
  • Turn On the Computer: Press the power button to see if the issue is resolved.

4. How can I check if my RAM is causing POST issues?

  • Turn Off and Unplug the Computer: Ensure the computer is powered off and unplugged.
  • Open the Case: For desktops, remove the side panel. For laptops, remove the bottom cover. Follow these safety guidelines when working inside your computer.
  • Reseat RAM: Carefully remove and reinsert the RAM modules.
  • Close the Case: Reassemble the computer and reconnect the power.
  • Turn On the Computer: Press the power button to see if the issue is resolved.

5. How can I run Dell Diagnostics to check for hardware issues?

  • Turn On the Computer: Press the power button.
  • Access Diagnostics: Immediately press the F12 key repeatedly until the Boot Menu appears.
  • Run Pre-Boot Diagnostics: Select Diagnostics from the menu and follow the on-screen instructions. If the diagnostic test fails, make a note of the error code, validation code, Service Tag, and then look up the error code.

6. What should I do if my Dell computer is stuck on the Dell logo screen?

  • Perform a Hard Reset: Follow the steps to perform a hard reset (see FAQ #3).
  • Disconnect External Devices: Remove all external devices and restart the computer.
  • Turn On the Computer: Press the power button to see if the issue is resolved.
  • Run Pre-Boot Diagnostics: If the computer turns on, access the diagnostics menu (see FAQ #5) and run a full system check.

7. What should I do if my Dell computer shows a black screen during POST?

  • Check Display Connections: Ensure the monitor is connected properly and turned on.
  • Use Function Keys: For laptops, try toggling the display output using the function keys (example, Fn + F8).
  • Test with External Monitor: Connect an external monitor to see if the display works.

8. What should I do if my Dell computer freezes during POST?

  • Perform a Hard Reset: Follow the steps to perform a hard reset (see FAQ #3).
  • Disconnect External Devices: Remove all external devices and restart the computer.
  • Turn On the Computer: Press the power button to see if the issue is resolved.
  • Run Diagnostics: If the computer turns on, access the diagnostics menu (see FAQ #5) and run a full system check.

9. What should I do if none of the troubleshooting steps work?