help! i just bought a new pc and it seems like whenever i try to run a game i.e.: NFS undercover or Underground2 or left4dead my computer slows down a lot and the audio starts crackling. the games run really smoothly for 2 seconds and then start lagging for 5 seconds and then goes back to normal for a bit and then goes back to laggy and it gets really frustrating! lol although sometimes they run perfectly i have no idea why the games lag like that even after i turn the game off the audio will still be choppy and make crackling noises i have nothing running in the background either. all the problems go away after i reboot though, but then they come back >:I PC specs: intel core2quad Q8200 @ 2.33ghz (not OCd) 8gb ram ddr3 ati radeon hd 4650 1TB hard drive Vista 64 bit (waiting for windows 7 to ship =p) please help me!!!