well, the laptop saw its arse and wouldnt play ball at all, ended up putting a dodgy new install of XP on it as a repair and it eventually started up, lost all manner of installed programs and files. Managed to delete the grot which was all that was really bothering me.
Anyway, guess what, my desktop has just reported the exact same problem, not starting due to system been missing. Followed collierm's instructions above and got the little bastard to get back to normal windows, keep getting loads of messages saying my antivirus cant update (ESET NOD32), then messages that google has stopped a program attempts to change my default search, then ask.com has stopped a programs attempts to change my default search. Ran chkdsk that repaired loads of stuff on the desktop. Cant work out whats going on