A bit of trivia on XP.
Apparently XP creates a hidden $logfile which equates to 5 or so meg per gig of disk space.
To see the size of your hidden $logfile open command prompt and type " CHKDSK C: /L " without quotes.
My C drive is 5.5 gig with the $logfile taking up 30,175kb.
As I like to thin out XP wonder if it can be resized.
Some info