Grab a Linux live CD of any flavour (chocolate, strawberry or Ubuntu/OpenSUSE/Knoppix) - boot your broken PC from CD. Mount your buggered drive (Just clicking on it in "Places" should do it (will be self explanatory when you boot)), and copy everything you need to an external drive :)
Easy as pie.
Then, once you have rebuilt - take Lucky_Fr4gg3r's advice and invest in Acronis True Image - fantastic bit of software, that.