I assembled an old PC for a friend using parts I had laying around for about two years. I put in a 5700 XT because I wanted to use my 3060 Ti elsewhere. After installing Windows, I noticed that every time I turn it off, it powers back on almost immediately. I've removed the only storage device and even disconnected the front panel connectors, but the issue persists. I also reset the CMOS battery. Any ideas on what might be causing this?
3 Answers
Make sure you're only using the PSU cables that came with your power supply. Using the wrong cables can send random voltages to different components, which might cause the PC to power back on.
Check your BIOS settings to see if something like 'Power On via USB' is enabled. Also, consider if it could be crashing when you try to turn it off and then booting back up automatically. You might want to look at the Windows event logs for any critical errors.
I removed the SSD and the problem still happened. I even unplugged all USB devices.
Just curious why you’re downgrading from a 3060 Ti to a 5700 XT? Also, have you verified that the power button is properly connected? You mentioned disconnecting it, but it’s good to confirm it’s the issue.
I’m giving the PC to my buddy, so it’s a downgrade in that context. Yes, I checked the power button connection; I even had to turn it on with a screwdriver while it was disconnected.

The PSU is non-modular, so all the cables are built into it.