Hey I too have a prob.I have 4 partitions......
C:18.6 GB(Windows XP Home)
D:9.3(Win 9

E:13.9(Backup)
F:13.9(Songs)
By selecting all files in C drive and checking it properties shows only 12GB occupied space.But in my computer it shows around 17GB where is the 5GB lost.
In F:/ drive I installed WinXP Pro 4 temporary purpose but to uninstall it I deleted it..........n it also showed tht it is deleting windows folder.....but it didn't put in recycle bin or even showed tht "Do u want to permanently delete it"........there is no folder of windows in tht partition........but still the space is not free........how to get it back..