. . puts its hooks way too deep into the system for my comfort. When I get a machine in for weird problems the very first thing I do is remove Norton anything to keep it from screwing with me. I don't reinstall it either, I tell the client s/he can reinstall it if s/he wants to.
A fun trick with Norton Antivirus: clone a hard disk with Norton AV installed to a different size drive (install Windows on the new, boot on the old and xcopy everything. Boot to DOS and copy the registries to make sure). About 4 days later, Norton AV will wake up, see the boot and partition info is different, and restore the old versions. Cool - no disk.
Took an hour in surgery to bring the disk back the first time that happened to me. It isn't going to happen again.