That's wga. Either your OS was never registered with a key, or you had some virus or misconfiguration that failed a wga test. Sort of like the ones your system is forced into having when you update it, or install msn or whatnot. This will corrupt the system, (wga for xp is fairly recent) and I'm unsure how you can 'untrip it'. But afaik with vista and 7 once you fail the test the system poisons itself and you are forced to do a reinstall. If you have the option of entering a registration code there's your golden ticket. If not, you better pull the pop can off your xp disk and insert it into your machine for a re-do. xD