Notebook/Laptop reformatting problem...

Ok, I've got a Gateway Solo 1200 notebook/laptop,
and it has XP on it, but I want to completely
reformat the hard drive to put 98se on it.

I go to start, run, and type in "format c:"
then command promp opens up and this is what happens:

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WARNING, ALL DATA ON NON-REMOVABLE DISk
DRIVE C: WILL BE LOST!
Proceed with Format <Y/N> (I click Y and hit enter)
Verifying 9585M

Format cannot run because the volume is in use by another
process. Format may run if this volume is dismounted first.
ALL OPENED HANDLES TO THIS VOLUME WOULD THEN BE INVALID.
Would you like to force a dismount on this volume? <Y/N> (I hit Y)
Cannot lock the drive. The volume is still in use.
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How do I get around this?
All I wanna do is reformat the hard drive...