Computer Shutting down and rebooting

[Meresgi]

I bought my girlfriend a new graphics card a few months ago, but her PSU couldnt power it. She had her brother inlaw put the card in, then he found out it couldnt be powered by that PSU, took out the new card and replaced it with the old card until i'm able to buy her a better power supply. Now her computer is just rebooting at random times throughout the day. I cant check inside her case because she lives a state away right now, but the only thing I can think of is either he didnt put the card back in right or something. Because swapping a card isnt that huge of a deal it shouldnt fuck up the PSU unless the newer card burnt out the PSU when she booted it up to try it out, and now its on its last leg.

[Tythera]

If you switched brands of cards it's probably driver related (use one of the driver remover programs in safe mode after uninstalling), if not idk

[Kirb]

It's either a driver issue, a PSU issue, or less likely, something completely unrelated, like the the cpu heatsink got bumped into while installing the new videocard and now it doesn't have full contact with the CPU anymore, so it's overheating. Hard to say without knowing more of the symptoms behind it.

[Shenrien]

I've had this happen to me in the past, it turned out to be the power supply, I didn't think anything of it at the time, but over the course of like... 2-3 years, it eventually blew out my entire system and I had to completely rebuild a 2000$ system.