How Can I Get Rid Of Green AV Update Pop-Up?

I have a problem with this Green AV Anti Virus update that keeps popping up on my desktop. I want to get rid of it but it keeps coming back. I tried going to Add/Rem Programs and used the search engine, but they didnt work either. The update shows every min and it wants me to pay $99.99 for it. Anyone know how to get rid of the update? Its very annoying.