Computer FREEZE or restart/ Memtest FREEZE

[sirkamran32]

Hey, i have a computer that i built. It has been freezing and restarting lateley. I did memtest, and THAT froze. I went out and purchased compatible high quality corsair RAM thinking that would solve my problem. THis failed, and my computer still freezes on memtest. When my computer does freeze it is usually during intense things like games or installing windows. When it freezes once, if I wait a bit, it helps, but if i immediateley start it up again then it freezes upon boot. This looked like a CPU problem, so when my computer froze i checked my temperature. That was way WITHIn the temperature limit, so my CPU is not overheating. I enabled "beeping" for my cpu temp and its voltage, and no beeping happens. However when i enable beeping for DDR voltage, my computer constantly beeps. Is this because of my power supply, motherboard or what? What should i do?? i dont understand what is going on!! ANY HELP APPRECIATED THANKS!!
Here are the specs of my computer:
Windows XP Home (SP2)
Intel Pentium 4 HT (3.06ghz, 2mb level 2 cache)
1 GB RAM (pc 4200, brand: pqi)
ABIT AL8 mother board
NVIDIA geforce 7600 gt
linksys wireless adapter
DVD read-write
150 gb hdd
350W power supply(i think...dont know how to check, it might be 400W but i doubt it)
ANTEC case

[JakeCourtney]

Did you reset the cmos? Try getting it to start up with safe settings in BIOS.

[sirkamran32]

ive done that. my computer starts up now. only thing is, my original problem remains...
the computer freezes upon intensive tasks.

[Ehart]

Did you ever find out what was causing this problem, i have also reset cmos and have all the same symptoms. Cant get through a memtest... How did you solve this ?

[vicec64]

Yes this could very well be a PSU going bad.

[sittas87]

looking @ detailed specs on a website it can be power failures cos you only have a 350(400w) PSU.Test your system on a higher PSU. even though you operating on one gig memory its still possible.
??