Or more precisely, it got hit by a virus, which was sufficiently virulent that it scanned the PC inserting its code into every executable file on the system, and spread onto attached USB thunb drives as well.
AVG didn’t spot it. Microsoft’s Live scanner found it but couldn’t remove it. I’m pretty sure all anti-virus scanners do it give you a false sense of security – I’ve now tried some scanners from McAfee, Norton, BitDefender and others (run from a clean machine) and none of them have been able to accurately find all the virus infected files.
Of-course this shouldn’t be possible. As far as I can tell the virus got installed when I ran an infected installer for another program, so even if I didn’t have admin rights as a user (which of-course I did have anyway, this is XP) I’d have needed to use admin rights to install it. I’m pretty sure that the same methods of infection wouldn’t be so effective in Linux but that’s my gut feeling not something I have confidence in.
It really shouldn’t be that hard to make it impossible for one application to mess with another application’s files. Certain files, like explorer.exe, should basically be untouchable (except via Windows updates etc). Each application should be restricted (“chroot”ed, in Linux terminology) to it’s own directory so that it simply cannot access files outside that area. I do know one thing: My Linux desktop, which I use most and which sees the most activity (email, software installation, etc) has not yet been vulnerable to the sort of viruses and spyware that seem prevalent on Windows.
So I’m mid-reinstall; I have XP installed, and SP3, and now most of 200Mb of updates; I’ve been working through the reinstall for several hours and I’ve so far needed 4 reboots and had to hunt down several drivers, for essential hardware like network, video and sound cards. Once that’s done I’ll be able to install basic apps like wordprocessors, PDF viewers, and the like. If only XP were actually ready for the desktop!