Ok, I just reformatted my computer like 4 times this month... it keeps happening

Like 2 days ago my computer would start loading Windows then just restart..

This morning (going by what my dad said) it wouldnt even start up (power?) and then it finally did but just kept restarting.

We just installed a new power supply (like a week ago, my old one broke) and a new SB Audigy 2 sound card...

Any suggestions of how to make it stop crashing??

And oh yeah, I only install like AIM, MSN, Firefox, and Mcafee when it gets back all the time... so its nothing im DLing

And dont tell me to buy a new comp, this one is only about a year old and im broke as hell