My PC auto-initiated an update to Norton 360. Something went horribly wrong, and Norton indicated an 8504,104?

[Insane_mad_maniak]

either disable Norton protection, not sure how you disable it as i haven't used Norton products in years.

online search suggests 'right click on the NIS icon in the taskbar and select Disable Smart Firewall' and you can also disable antivirus from there aswell.

you should then be able to use your internet and download the uninstaller, or the latest virus definitions which might have been updated and sort the issue out.

a restart of the computer might also work, some antivirus programs have this scenario in mind and put in an emergency boot updater that usually sorts the issue out aswell.

if none of this works. start in Safe Mode With Networking.

start the computer, Keep pressing F8 on startup (even if it beeps) and select 'safe mode with networking', you should then be able to do what you need.