You should check the antivirus software's webite to see if it's a problem that has happened before. Can you get on any websites? Have you used that software before?
You might also have some kind of adware/spyware that is making it go plooey.
If you aren't loyal to that antivirus you could try another. I use AVG (by Grisoft). This is their
website where you could download the free version to test drive it. I've never had any problems with it.