Vista to xp on new laptop

Hello, I got a Dell Inspiron 1525 lap top in Feb. Had unbelieved trouble with the vista (still do) couldn't get newer Hp all-in-on printer to work. I finally figured out how to get it to just print, both nothing else works. I guess M.S finally got tired of me, so they sent me a new Windows Xp Professional disc, 2002 version with service pack 2. But they didn't tell me how to install it. I've tried looking on line and keep hearing about changing drivers. I know I have to back-up & copy all my files, but I'm scared to touch anything else. I go to college & am coming into finals with terms paper etc. If this thing goes, I'm in big trouble. Can someone give a kind of step by step deal on how to switch. Really! hate MS Word Processor, what a waste, can't interact with any of my school stuff. Plan to get back Word as soon as I get this switched. But in the mean time, I need a little help here.....Please.....
Thanks Q