ok so i just did a fresh install of xp sp2 and updated to sp3. installed all drivers for all my hardware and my antivirus. now to the problem while playing cs source i get lag. but not all the time. only when i move the mouse. if im just walking or spectating everything runs great. but the instant i move the mouse it jumps bad. i tried in hl deathmatch too and same thing. i am using a setup i have played this on perfectly before. my mouse is a g5 laser. i tried re installing the os again. and disabling my antivirus. im running out of ideas on what it could be. any suggestions???