If there putting in new motherboard thats a bit more serious and I'd go for a new Windows install too.
Motherboard usually incorporates disk controllers, sound card, USB sockets, ports, maybe even network card and modem etc so there's quite a few drivers to make 'em work right.

If they do have to re-install windows you'd not lose any MP3s, vids or piccys though. that shouldn't be touched.

steve