XP I take it?
Something is wrong with the paging file, it's the same 17 damn updates that aren't installing properly. And by something I think it's that the hard drive is full
Minty, do you know how to burn a cd image to a CD? Vista and 7 can handle them without software, I believe. Anyway, if so, go to www.ubuntu.com
and just download the netbook edition. You can boot off the CD and your kid can go to lego.com or whatever, and you won't ever actually use the hard drive, so previous adware and such won't run and he won't be able to do anything permanent to the machine.