How do I remove this program?

I clicked on something, it said it was windows, I thought it was an update or something. It installed something called personal antivirus (PAV). I know stupid. Then I found out I don't want it! It won't let me acess my ISP email and several other sites that have caused me not problems with spyware. I've clicked the uninstall, nothing, I looked on the add/remove list to remove it, it isn't there. How do I get rid of it?

 

Thanks Matt. It immediately blocked this site when I posted, so I did a search, some sites it blocked, didn't think I was going to be able to do anything about it, but I was able to find it is a virus and downloaded something to get rid of it, now it's all gone.