I need help

Ok, in more ways than one. But, my major issue right now is...my laptop "crashed". It has a virus. The guy at Geeksquad stated that if I reinstall Windows XP it should run fine again. That is GREAT news however, he stated also tha once I did reinstall that it would delete my files...forever. Now I am doing some research and am finding out there are ways to recover that lost data. This i where I need your help...where do I get the program from and if I can't boot my PC how can it recover anything?!?