I ran MacAfee registry cleaner program and then re-started computer. The blue Welcome screen came up. When I tried to open my personal account it opened for a moment and then proceeded to logging off. I tried opening another account with the same results. Also tried to open in safe mode, last known settings, etc., etc., with no success. Does anyone know if I can change boot sequence? Do I need to reload XP? (Cannot find XP disc!) If so, do I need to reformat? How? Will rescue disc help?