DRIVECRYPT - missing memory

I use an 40 Gig IMB lap top and XP

I recentlty installed the new drivecrypt programme which is working
well.

However, since I was messing around with it I notice that a chunk of
my lap top's hard disk drives memory seems to have been eaten up.

I have one main drive only, Drive C, onto which my active Drive Crypt
container (Drive W) is loaded, along with everything else (files,
programs etc).

When I add up the memory of all the programms and files (hidden and
unhidden) listed by "My Computer" as being saved on Drive C it comes
to about 17 gig of stuff. That seems about right. This 17 gig
includes the 9 gig container which drivecrypt uses (Drive W) for my
encrypted material.

Yet "My Computer" shows Drice C as only having 2 gig free space now,
whereas I would have expected it to show about 18-22 gig free...in
other words I can's account for almost 15 - 20 gig of hard disk memory
which seems to have been eaten.

Anyone any ideas what's going on?

I can only think that:

1. i have inadvertantly created an invisible drive (can I check?); or
2. when i deleted a couple of unwanted "test" containers in the early
days, the hard disk still reads the space as being used; or
3. My computer is incorrectly showing on 2 gig as free space, and
there is in fact loads more.

Any advice would be gratefully appreciated.

Cheers

Supachai