Well, I have the same video card in my gaming box as you and have no problems, but I'm using newer drivers (the 52.16 drivers you have had some bugs), so give that a try. Grab the 53.03 drivers from Nvidia over here;
53.03
Could also be your ram timings, considering that it does not always happen to you, either that or heat. You may want to open up your box and blow all the dust out of your heatsink and clean off your fans. Since its an alienware box I imagine they cranked up your ram timings, you may want to hop in the BIOS and relax them a bit. i.e. If they are at 6-2-2 cas 2 drop them down to 8-4-4 cas 3, or 7-3-3-cas 2.5. Its a quick and easy fix.
You may want to scan your drive for errors as well (sometimes there will be a error on the disk in the midst of the region designated for the swap file)
hit start->run->then type 'cmd'
->hit OK- type 'chkdsk c: /r', then agree to have it done when you reboot (dont type the quotes). Go reboot and wait a while. You have enough ram not to need the swap file, but unless you've set a few settings in the registry windows will use the thing like an idiot even with a couple gigs of ram available....
Good luck
