You may have to burn a fresh backup of Norton from another computer, then install and run on yours.
Barring that, google the hijack site from another computer and see if there are alternatives. Sometimes you can manually expunge hijacks without in-depth knowledge. You can go to Norton's site then search the site for the hijack address.
Barring that, copy all the data off of your system and reinstall XP. Make sure you can retrieve the data from the disk you burned before you reinstall, as reinstalling will wipe your disk. Best to upload the data to another computer before reinstalling. Next connect to microsoft.com to get Service Pack 2 and MicrosoftAntiSpyware. Then get Norton or a freeware antivirus program (
www.majorgeeks.com has it all). Configure the internet settings. Then get Mozilla's Firefox browser so you don't have to deal with most hijackers. Then get Spybot Search and Destroy, SpywareBlaster, ewido security suite and blacklight, all freeware. I like BHODemon too.
They can still get you pretty easily, but your house isn't safe either.
Matt