Question PC turns itself off and on repeatedly after replacing graphics card and then putting old one back

Aug 1, 2020
I have a PC with a GA-Z170-Gaming-K3 motherboard, 650W Corsair VS PSU and Gigabyte NVIDIA GeForce GTX 960 GPU.

The fan on the GPU was making a really loud squeaking/cricket chirping noise which I believe was related to the bearing and it was getting worse over several weeks, so I bought a Gigabyte NVIDIA GTX 1060 to replace it (as the GTX 960 no longer appears to be available). I looked it up beforehand and found that it should be compatible with my PSU.

So I uninstalled the NVIDIA Graphics drivers as recommended by NVIDIA, put on my anti-static wrist strap, removed the old card and installed the new one. The only real difference was that the cable from the PSU is a 6 +2 pin cable not an 8-pin cable, and the old GTX 960 used a 6 pin whereas I had to use both the 6 and 2 pin cable for the 8-pin slot on the GTX 1060.

I started the PC up again and it turned on, whirred for a couple of seconds and then turned off (fully cut the power), then turned itself back on for a few seconds, then turned off again. It kept doing this several (10+) times without any input from me. During this time the GTX 1060's "Gigabyte" logo lit up and also the "Fan Stop" light was lit up, but these turned off with everything else whenever the power seemingly cut out.

So I removed the new graphics card and put the old one back in, but it keeps doing the exact same thing and I can't get it to turn on successfully.

The motherboard doesn't appear to be at all damaged, and both the cable to the PSU and PCI-E connector to the motherboard appears to be plugged in securely. I checked the pins on the PSU cable and they all look fine, none seem bent or anything. I even tried switching to the second 6-pin cable plug in series (the cable from the PSU has two) but this did not help.

I must admit I was expecting a pretty simple removal and installation and never imagined I'd make my PC unusable even if I switched back to the old card. I was gaming on it this morning and it worked fine other than the annoying chirping noise.

Any ideas as to how I can try to fix this?

EDIT: I have tried removing the graphics card completely and connecting the monitor directly to the HDMI port at the back of the PC but it is still turning off and on again repeatedly whenever I attempt to turn it on. It does not "beep" at all during this process.

I have also checked for screws and exposed wires in case it's a short circuit but I can't find anything out of the ordinary.
Last edited: