The best way of doing what you want is to not reformat the drive. A
product called "Partition Magic" allows you to re-partition your hard
drive with NO data loss! It works! I've used it myself!
The product "PartitionMagic 8" can be found here:
It costs $69.95USD, and worth every penny. Simply install the
software, and 'Resize' the partition to fill the entire drive. 'Apply'
the change, a quick reboot (ok, so maybe not "quick", but definitately
faster than backup/restore), and voila! It's done!
To do it the old fashioned way, you'd need to use Microsoft Backup to
backup your entire 15Gig partition to your USB drive. Then, ensure
that you have created a Windows 98 Boot Disk (floppy disk).
Instructions can be found at Microsoft's Tips & Tricks site for
Windows 98 which is found here:
Next, boot with the floppy disk you've created, ensure that you can
read the CD with the Windows 98 Install files(!), then format drive C:
by using the command:
FORMAT C:\ /q
Once done, Reinstall Windows 98, and once re-installed, launch the
backup utility and restore from your USB drive.
If you can get your hands on a drive that will work from DOS (another
internal harddrive), you can also try the following full-system
restore function, found on Microsoft's Knowledge Base called, "How to
Restore Windows 98 from a Full System Backup":
Honestly, for $69.95, go for the PartitionMagic Software. It's worked
great for me! Do the backup anyways though!
If any part of this answer is unclear, please ask for clarification
prior to rating the answer.
(PartitionMagic was previously known by myself, so no search was
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