New Mainboard–Old Hard–Drive

My Hard-Drive IBM 40gb 7200rpm ATA/100 has about 5 gigs of Programs/Apps./and personal files. I just purchased a new Case w/400w PS. with a new Mainboard w/2.4Ghz P4-CPU/512mb ram. Question; Can I use my Hard-Drive without loseing any Data ? It has XP-Pro installed that I want to keep. Along with Office 2003 and many other Programs. Will it boot-up and all is good? Or ??? Thanks for the help. Kenny