Backup

I have one toshiba celeron laptop , the problem with the laptop when you start windows comes only the windows xp screen and it seems to be starting winxp but suddenly whole screen goes black
I tried to put restore cd on it but it asking me to rebuild rather than repair so that i can save all the Doc and Excel files that has been created in.
Is there any way where i can backup of all doc and excel data before reintall the win xp.