All files, documents and programs I'll need didn't even take up half a DVD, so I made a back up of all my disquette games just in case, of course think take up must space either...
Then I remember that I had bought the downloadable version of Half Life 2, so I thought it was better to back it up as well. Backing up all the games I had on my Steam account took hours and several Gigs, enough for almost 3 DVDs!
But it's over now, all I have to do is wait for my sister to bring back the motherboard and hope nothing goes wrong. I only have one flimsy manga tome to keep me entertained while I reinstall everything, I wish I hadn't read that Terry Pratchett book because it would be perfect for now!