If you have every thing you need backed up, then just do the destructive system restore. When windows reloads, take off norton.
You will need to re-install all your settings and programmes.
Then think about using McAffee from AOL.
If you have data you wish to keep. You could either
try a windows repair if HP gave you an OEM disk
put the hard drive into another computer to salveage the data you need. Then pop it back into the HP machine and do the destructive restore.