I'm starting my first job this Wednesday, and shortly after finishing the interview my desktop suddenly went black while I was playing a game. The fans and lights stayed on, but the monitor stopped displaying and the keyboard's lights went out. This has happened rarely before, but the computer normally recovered.
This time, holding the power button did nothing, so I unplugged the PC. After reconnecting it, the speakers and headset lights came on, and the monitor showed its startup logo before going black again, but the keyboard remained unresponsive. I repeated this several times and also cleaned the system, heatsink, and fans and reapplied thermal paste, but nothing changed. The keyboard works normally on other computers. I don't have transportation to a repair shop, so I'm hoping to troubleshoot this at home.
3 Answers
A power supply can partially fail even if fans, lights, and speakers still turn on. It may not be providing stable power to the graphics card, motherboard, or USB devices. Check for loose connections and, if possible, test with a known-good PSU. A PSU tester can help, but a paperclip test only shows whether it starts—not whether its voltages are correct—so be careful and don’t open the PSU itself.
The system is probably failing before it completes POST, which explains why the keyboard never lights up. The most likely causes are the power supply, RAM, motherboard, or graphics card—not overheating, based on what you described.
Start by disconnecting nonessential devices and drives. Then test with one RAM stick at a time, trying each stick in different recommended slots. Reseat the graphics card and power cables as well. If your processor or motherboard has integrated graphics, try booting without the dedicated graphics card. Also check whether the motherboard has diagnostic LEDs or beep codes.
There are no beep codes or warning lights that I’ve noticed. The fans and other RGB devices power on, but the keyboard stays completely dark and the monitor only shows its brand logo.
Try resetting the CMOS by removing the motherboard battery for a few minutes with the PC unplugged, then reinstalling it. You can also try a different power cable or surge protector. If the power button still won’t shut the machine down and no combination of RAM or graphics tests works, the motherboard or PSU is probably the issue.
Since you need a computer for work soon, contact your employer now and ask whether they can provide equipment or let you use a temporary laptop. That gives you time to troubleshoot without risking your first day.
The computer went black in the middle of a game, but there wasn’t a burning smell or any obvious overheating warning. I may try testing the power supply, though I’ll make sure to follow the instructions carefully.