I've been using this windows 7 desktop for over a year, and everything has been fine until the past few days. When I minimize a program or when i maximize it when it is minimized, the program lags. For example, when I am running firefox and when i click the minimize button, instead of firefox minimizing in a swift motion, it minimizes slowly in other words, lagging. Also, when I play Warcraft the game lags. It lags in a really strange way, almost as if the game is drifting around when I move my mouse. Usually when games lag, the controls you make respond slowly, or it is in a jerky kind of way. I've tried restarting my computer many times, and all is well for the first 15 mins or so, before this lag kicks in. Any help would be greatly appreciated.