Well ive tried everything i can think of... i just bought A package of games from bestbuy, which includes cs source, DOD Source, Hl Deathmatch, and some other games... i put them all on my computer and it all went smoothley with no errors... when i try to play them however.. the gameplay is verry choppy and the sound skips... its not internet lag because it happens on on an offline game also.. My comp can run CS CZ and it has for along time.. no problems at all.... i try to contact steampowered but there technical support is ****.. dose ne1 have any sugestions... if you do, plz let me know...