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.
Will the netbook edition run on a regular laptop? They used to do a hardware check for Atom CPUs but if they've removed that restriction then this is a great idea.
Sounds like a great idea for his wife, too