A friend of mine is a WoW player. Whenever he runs the game, two or three minutes into it, especially when he does something graphics intensive, the computer reboots. He said he was experiencing some artifacts. The video card was a gift from me, used, about three years old now. We replaced the video card and the artifacts disappeared. The game will now freeze. Alt-tab is unresponsive. I have not had him try ctrl-alt-del. We reinstalled the game, no addons. Issue persists. I think the next step is to run another graphics intensive app and see if the problem persists. If it does, I'm thinking a power issue. If it does not, maybe a sound issue? Any advice on how to proceed would be appreciated. Thank you in advance.