First of all, do not pay $120 for 512mb of sdram. Yo can buy the stuff on Ebay for dirt. When is the last time you defrag'd your hard drive? I would be looking at the possibility that you have spyware running in th back gournd and I would suggest, if you have not already done so, buying a spyqare detector/cleaner such as Aluria or Xcleaner et. al. The other issue is the video card! You should really consider getting a newer card. Nvidia 6600gt's are going cheap these days so.......finally, is this a new problem or has everything been kosher until just recently?
Noli Nothis Permittere Te Terere!!
EVGA 680i, Dual EVGA 8800GT'S (650/950), 4 gigs OCZ DDR2 1066, Intel Q9450 at 3.8 Ghz, Koolance Water Cooled, Dual Plextor16x DL DVD+/-RW. Dual WD 250gb 16mb Cache Sata 3.0. 3DMark06 score = 19,168.