Backup - restore question

After I did a clean install of XP Pro and a bunch of
applications and set up my system the way I want it I did
a full backup of the "C" drive.

After using it for a while I appear to be having problems
so I want to revert back to this full backup state.

What's the best way to clean out everything in C and bring
in the backup file from DVD?

There must be an easier method than reformatting the
drive, doing a clean install, and then a restore from
backup.

Marc