For all those who helped me with the power supply problem, thank you very much. It did end up being a bad power supply, so it's all working now. There is one problem that has surfaced since installing Windows XP, however: When I scroll down on an internet page or move a window, it gets very glitchy. The window moves very slowly and blankness is left in its wake for a few seconds. When I scroll down, I experience a similar problem. Any ideas as to what I could do to eliminate this problem?