Hi friends.how to unlock bit logger encryption in xp which is encrypted in windows 7.?

hi friends.how to unlock bit logger encryption in xp which is encrypted in windows 7.i did bit logger encryption in my drive f; in win 7. after that i changed my o s to x p . now i try to open that drive in xp (f; drive encrypted) it says to format the drive . how to remove encryption in drive f; in xp.and how to open and acess the drive f. which is encrypted in win 7.