I just finished building a new PC. On the first boot, it powered on and displayed the BIOS, but I couldn't get it to boot from my USB installer to install Windows. After restarting several times, I shut it down and stepped away. When I returned, the fans, lights, and GPU powered on, but there was no display. I tried clearing the CMOS with the button on the motherboard's rear I/O panel, and now the motherboard shows a yellow diagnostic light. I've tried connecting the monitor to both the GPU and motherboard, reseating the RAM, and removing the GPU, but still get no image. What should I check next?
3 Answers
Fully shut the system down, unplug it from the wall, and hold the power button for about 30 seconds to discharge it. Then check that the motherboard’s main 24-pin power connector and the CPU power connector are firmly seated, including any detachable section of the cable. After that, try booting with the minimum hardware: one RAM stick, the CPU, and the GPU if the processor has no integrated graphics. The yellow motherboard light should also be checked against the board manual, since it usually identifies whether the problem is memory, CPU, or another component.
A powered-on system can still have a loose or improperly connected power cable, so lights and fans don’t prove that the PSU is supplying everything correctly. Static is less likely to have suddenly damaged the PC, but working on a rug can increase the risk of static discharge. Avoid repeatedly changing several parts at once; inspect the connections, clear the CMOS according to the motherboard manual, and use the diagnostic LED label to narrow it down.
The PC is sitting on a desk, but the room has a rug. I wasn’t sure whether static could have caused damage between the first and second boot.
Make sure the monitor cable is connected to the graphics card rather than the motherboard video output. Since the GPU connection worked during the first boot, that’s the one to test first, though this alone may not explain the new failure.
I tested both connections. The GPU output worked on the first boot, but after returning with another bootable USB there was no display. I also reseated the RAM and tried removing the GPU completely.
It’s confusing because everything worked during the first boot. Could the power supply still be involved if all the fans and lights turn on? I’m also wondering whether the yellow light points to the CPU or RAM.