Ok, so, the problem is this. His computer is a dell inspiron 600m laptop. And he uses it to play games. However, lately it has been doing something very strange. From the time he turns it on to about 30min into playing a game, his computer acts normal, then after that time his computer "enters lag-mode" (that is what we called it). Basically what happens is that it slows down the game by about 90%. Things move real slow, and in a network game, it effects everyone else as well. But we know it is him because when he plays a game by himself it still does it. It acts very much the same as if the powercord was unplugged and it was running on battery. So I took the battery out (thinking it was battery related) but it still occurs. We tried looking for viruses, addware, and spyware. That wasn't it. I also checked the running processes, nothing was abnormal. But it still goes into lag mode. The weird thing is that it gets worse and worse, first 30min of fine play time, lag mode, then 25min, then fine, then 20... and so on and so forth. The other weird thing is that lag mode lasts only for a pretty regular amount of time. Its like clockwork... But I am out of ideas.
Does anyone have any other suggestions?