Every 3 or 4 days I get a message pop up when XP has finished loading. The message is as follows: 'Files that are required for Windows to run properly have been replaced by unrecognised versions. To maintain system stability, Windows must restore the original versions of these files.' All I have to do is stick the disc in and the message disappears. There is no hdd activity and I can remove the disc straight away so nothing is being copied over. I have not installed any new programmes and the message just appeared out of the blue. Could it be a Virus or is it a way for Microsoft to make sure you have the original disc and you do not have a copy?