Formatting Question

[Ryan Bingham]

How do I get to the MSdos program so that I can format my
c drive. I've already gone to the command prompt window.
I typed format C: and it gave the warning about losing
everything and I saide yes, and also it said the volume
was in use by another program. It asked if I wanted to
force a dismount of the volume and I said yes. It said
that I can not lock the drive and the volume is still in
use.