Get it OFF my Mac! HELP!

I installed Snow Leopard, then installed Antivirus for MAC.  BIG MISTAKE!

 

It is constantly intruding with a reinstall Norton message.  I did that, once--and how the message prevents me from doing ANYTHING on the MAC.

 

Since I really am a neophite on a Mac, I'm really in a quandry.

 

How do I uninstall the Antivirus--get it off of there completely?  I have stuff I need to do on there, and can't even get email without the message.

 

I am writing this on a PC, by the way!

 

Please help!

 

Thanks!

 

Pleenpa