It's spyware till proven otherwise. My experience is that Norton is no good at detecting these.
Get Spybot S&D and AdAware, both free. Run them in safe mode. Run Norton again in safe mode just to be sure.
If those don't work, get SpySweeper, run the free version to see what it detects. You have to pay for the version that actually removes stuff, but it has been worth it to me.
As noted above, if you google the name of the offender, you may get some pointers on how to remove, but often the advice was beyond my simplistic skills.
I think they should hang people who invent that cr*p. And I wouldn't care if their heads fell off during the process.