Blue screens, lockups, need help finding the source


Sep 30, 2011
Hey all, first time builder and I'm running into some issues with my new rig.

I put it together less than two weeks ago, and it's been running fairly well. When it's working it's acting beautifully, and running pretty much any game I throw at it without any hiccups. But I've been having reoccurring problems with it. Sometimes it's bluescreens, both while in Windows and while booting up. Sometimes, usually when I try to turn it on, it seems to boot up since the fans start spinning and I can open the optical drive, but I get no feed to my monitor or keyboard (since I can't get the num/caps/scroll lock lights to light up). Sometimes it'll just lock up, usually while I'm playing a game. When this happens the screen freezes, I can't move the mouse or alt-tab out of the game, and the sound goes to nasty distorted gibberish.

The blue screens I get are DRIVER_IRQL_NOT_LESS_OR_EQUAL, and it points to a file called nvlddmkm.sys. The other one I get, though I haven't gotten it nearly as much as the 1st, is PAGE_FAULT_IN_NONPAGED_AREA.
These two make me suspect a faulty video card or drivers, but I would think that if it were faulty hardware that it wouldn't be performing as well as it has been. As for drivers, I've downloaded the latest drivers from nvidia and done clean reinstalls twice but to no avail. I've also tried reinstalling Windows itself, but all the problems persist.

As for the lockups, I suspected my card to be overheating but when I monitored it while in game, the temp I got just before locking up was 52 C. And concerning the loss of video feed, I have no clue what it could be.

Antec Three Hundred case w/ top and rear fans
Mobo: Gigabyte GA-870A-USB3
CPU: AMD Phenom II X4 955 Black Edition w/ stock heatsink
Video Card: EVGA GTX 460
RAM: G-Skill Ripjaws DDR3 2000 4gb (2x2)
PSU: OCZ ModXtreme Pro 700w
HDD: Seagate Barracuda 7200 rpm
Windows 7 64 bit

What's causing all these crashes and freezes, and what I should do about them if it's something more than just bad hardware?
Hopefully I was detailed enough for anyone who's willing to help. And thanks in advance.