That doesn't make any sense.
Norton is not working, so rather than resolve that problem, you are going to unpartition the drive?
Oh well, I'll just address what you asked then.
Format the HD. Easy.
I think FWB Hard Disk Toolkit can partition without data loss, so maybe it can 'unpartition' too. I dunno.
Why can you not run Norton?
Install systems on both partitions - boot from one, defrag the other. Repeat with other drive...
Oh yeah, get a better defrag tool too... like TechTool 3.