System Crashing,reason unknown

[KuKuBuKu]

Ok, I built my computer a couple weeks ago, and it began crashing (Not often) and now it is starting to crash a lot. I've checked the computer for viruses, I cleaned the registry, all to no avail. I'm thinking it may be an overheating problem, as after I didn't use it for a day, it took a long time to crash. Despite this, the graphics card is absolutely fine, running at the upper 30s, lower 40s idle. CPU is in the lower 20s idle. My specs:

ati radeon 5770 (Asus)
Phenom II tri core @ 3ghz
Asus m4a79xtd evo
4gb ddr3 ram Gskill
Logysis area 51 case
500w Psu apevia
Windows 7 64 bit home premium oem

 

[jsphdickens]

It doesn't seem like an overheating problem, but if you want to monitor your temperatures under load I recommend RealTempGT.

What do you mean by crashing? Locks up, blue screen, shuts down, etc...?

 

[rolli59]

Your PSU, although being big enough, is Apevia which can not be called a quality unit and therefore suspect. You description, did not use it for a day took long time to crash, points that direction since CPU and GPU temps are fine.

 

[aford10]

Boot into safe mode, and check the event viewer for errors.
start-->run-->eventvwr.msc-->check the system and application logs for red X's.

Does it crash while in safe mode?