something odd

[Zippoh]

Alright my HDD has 232GB of useable space.

Programs: 10.9GB
Windows: 16.7GB
User Data: 2.27GB
Total: 29.87

so in total I'm using 29.87gigs, which would mean I should have 202gb left...but it shows I have 153gb left?

so where did the rest of the gigs go?