if the memory checks out OK, another thing to try is updating your drivers to the newest versions. You can get the one's for both your video card and motherboard chipset here: Nvidia Driver Downloads
Went to install new drivers for mobo from that site, and under "Current Version" was nothing, so i have installed the latest version, and will see how that goes.
Currently installing latest version for my Gcard too.
You say beeps at start up. If you get more than a single beep at boot up the POST system is trying to tell you something's wrong. What is the pattern of the beeps?
IRQL; wouldn't that lean towards IRQ assignment issues? Possibly a faulty BIOS causing resources to be improperly distributed. I'm no IRQ expert, but that's the vibe i'm getting here.