chkdsk quite nifty.
In XP (right click c drive -> properties) also shows the
drive size in Bytes and GigaBytes.
Be careful about moving decimal points with bits, Bytes,
Gigabytes etc. you may want to use a program like Convert
http://www.joshmadison.com/software for more accurate
conversions. A clasic example is the 4.7 Gig DVD rom which
realy is 4482 MB or 4,700,000,000 Bytes. So move the decimal
point a few places to the left 4.7 Gig was born offering a
.323 Gig of phantom space.
slippery