How to Troubleshoot No POST or System Startup Issue on a Dell Desktop

In a well-lit environment, the monitor might be on, but the screen could appear blank because the display brightness is set to its lowest level, making it seem like it is not turned on.

All monitors have brightness and contrast controls. The location of the brightness settings in the menu may vary depending on your monitor model.

Below are generic steps to locate and ensure that the brightness level is at its highest.

1. Press the bottom-most control button either on the front or right side edge of the monitor.
2. Press the button to the right of the Menu (make note of any Model number showing).
3. Look for the Brightness and Contrast settings. Ensure that the brightness is set to its highest level.

If you have another monitor available, disconnect the current monitor, and replace it with the other monitor. This helps eliminate several factors that might prevent a video signal from reaching the original monitor. When the monitor you are testing with works, ensure all the settings on the original monitor are correct and that the cable connections are secure. See the manual for your monitor page for how to change the settings.

For more information, see Dell Knowledge Base article How to Connect a Monitor to a Dell Computer.

If you do not have a second monitor to test with, go to the next step.

Ensure all the air vents are unobstructed. Excessive heat can damage the internal components such as the CPU, Power Supply, and cooling fans. Overheating often occurs when dust or debris is blocking the air vents, exhaust ports, or the fan is clogged. To prevent overheating, keep the computer on a hard or sturdy surface, and provide adequate clearance around the air vents.

See the video and the instructions below on how to ensure that the air vents are clean.

1. Disconnect the AC adapter.
2. Check the air vents on the computer for dust or debris.
   Vents may be located in various places depending on the computer model. See the User Manual for your Dell computer.
3. Use a can of compressed air to remove dust or debris from the air vents.
   CAUTION: Follow the instructions on the side of the compressed air can, as using compressed air incorrectly can damage your computer.
   CAUTION: Do not try to blow the dust off with your mouth, as the moisture can permanently damage electronic or electrical components.
   CAUTION: Do not use vacuum cleaners or blowers. Vacuum cleaners and blowers cause static and may damage electronic or electrical components inside your computer.

For more information, see Dell Knowledge Base article How to Troubleshoot Overheating, Shutdown, or Thermal Issue on a Dell Computer.

Has any new RAM, a hard drive, or other components been replaced or updated recently? If your desktop stopped working immediately after the hardware change, there is a chance the new hardware is faulty or was installed incorrectly.

When you installed the component yourself, you may want to try to reinstall the component. See the User Manual for your Dell computer for detailed information about disassembly and reassembly.

Dell offers videos for some computers to help guide you through the replacement of parts such as the battery, Hard Drive (SSD), or keyboard. See our Support Video Library, once there, search the videos by the model number of your computer.

For out of warranty repair service, see Dell Knowledge Base article How to Arrange an Out of Warranty Repair on Your Dell Computer.

If you are comfortable opening your desktop, you can try reseating the RAM modules to see if that is causing the issue. See the User Manual for your Dell computer for detailed information about disassembly and reassembly.

Dell offers videos for some computers to help guide you through the replacement of parts such as the battery, Hard Drive (SSD), or keyboard. See our Support Video Library, once there, search the videos by the model number of your computer.

For assistance with repair options', Contact Dell Technical Support.

The desktop motherboard includes a small circular battery that powers the CMOS chip, which stores settings like the date and time, fan speed, and boot sequence. This is essential for the BIOS to load the operating system and manage all input and output components during bootup.

If this battery is dead, it can potentially prevent the desktop from powering on.

If you are comfortable opening your desktop, you can try replacing the CMOS battery to see if that is causing the issue. However, most people opt to have it replaced by a technician.

See the User Manual for your Dell computer for detailed information about disassembly and reassembly.

Dell offers videos for some computers to help guide you through the replacement of parts such as the CMOS battery. See our Support Video Library, once there, search the videos by the model number of your computer.

For assistance with repair or replacement options', Contact Dell Technical Support.