desktop problems..... think its the psu

[di$TOrTed]

My friend's desktop is having problems. Sometimes it won't start up at all, and other times it will start and only go to like the startup screen. Also we noticed that the keyboard and mouse dont even power up on start up. Rarley it does actually start windows xp up but within 5-10 mins it just freezes. The screen also spazes out sometimes going into a black and white checkered pattern. And also sometimes it wont even power up or it will power up and not power up the screen. We did a quick check on everything inside to make sure they are all properly plugged in and what not. Please help us figure out the problem before we spend 100s of dollars on it and still end up with a broken piece of shiza.

Specs:
OS: windows xp w/ service pack 2
2.5 p4 1 gig ram
sound blaster audiogy
ati radeon x700

 

[2048Megabytes]

I am not saying this is your problem but here are some signs of a failing motherboard or processor:

The system begins to boot up but then powers down

An error message displays during the boot (Investigate this message)

The system becomes unstable, hangs or freezes at odd times

Intermittent Windows or hard drive errors occur

Components on motherboards or devices connected to it don't work