No offense, but "upgrading" to Norton isn't really a good idea, especially since Kapersky know supports Windows 7.
Do you have another restore point to go back to?
Try searching for leftover entries from Kapersky and also check msconfig, and services for any entries there.
Did you create Image Recovery disks?
Try tapping the F8 key (will be different for other manufacturer's computers), but this will bring you to the screen with Safe Mode, Safe Mode with networking, etc.
Try the first entry....Repair my Computer, then try Startup repair, System Restore, or system image recovery.
If this doesn't work, try Safe Mode on the first screen.