So I have this Gateway CPU that I am trying to get working again as it had problems before.  What happens is it randomly seems to freeze WITHOUT warning and is unusable until I manually power down the system.  I eventually wiped the hard drive and reloaded the OS (Windows Vista 64 BIT).  The problem is still there it happens after the CPU loading screen when it tries to LOAD the OS or ANYTIME after that right now I cannot get into the OS because it freezes first, I can access the BIOS fine though.  The other bit of news which is pretty important is that I foolishly bought a graphics card which requires 400 W of power minimum according to the box, but my power supply is only 300 W.  Before I knew this I ran the system for a least a straight month and then off and on for another couple months without any problems even though I was using the graphics card (PNY Nvidia Geforce 9800GT).  Today I took out the graphics card but I still froze.  So any advice is helpful, I am wondering mainly what is causing the freezing now, and if I seriously damaged something by running the card with inadequate power.  The RAM seems fine and the temp hovers around 40 Celsius if that is helpful
ThanksBorrow a known working PSU of at least 400W or greater and swap it in there overnite...
You will know right away if thats the culprit...

You are asking that hardware to do something it's not quite capable of...