What could be causing my friends computer to crash?

I would suspect these things:
power supply
RAM has become unseated in the sockets / mild corrosion on RAM sockets.
hard drive connection / hard drive failure

I’d try pulling the RAM chips out and reseating them first, when that’s the problem it’s so easy to fix it’s worth trying up front. The seasonal change in temp/humidity can cause RAM modules to shift out of whack. The symptom that it will crash in the first few minutes supports this possible cause, as maybe when the machine warms up a bit the RAM gets better contact.

A power supply can start going intermittently. But I think that would be more likely to quit after the machine warms up.

Hard drive connections can get intermittent, reseat the cables into the hard drive(s) at both ends.

Check for loose connections and if you go poking around inside make sure you are “GROUNDED”.

I use a VELCRO strap with a wire under it on my wrist and the other end on a ground source ( ground leg of an outlet or metallic cold water pipe ).

More than hardware problem, I would suspect a deeply entrenched malware or more running in the background. Try booting the system in Safe Mode with Networking….if the system does not manifest the problem then surely there is the high possibility of rogue apps running in the background, undetected by antivirus software….. While running on safe mode, connect to the internet and download an anti malware software, i.e. malwarebytes, hitman pro, avast, etc….from download.com. Scan system and rescan after rebooting.

It is the power supply box, I noticed a surge before it froze. Thanks for the help.

Surge protectors and oversized power supplies are your friend. My 600w unit can supply the 450w I need more reliably, and can handle things that would fry a PSU that was closer to my actual needs. Also, go name-brand; they cost more, but the others are cheap for a reason ;)