There are so many antivirus and other malware software applications out there it is near to impossible to keep up with them all. Many if not all have removal tools to use in case their normal uninstall process fails.
Here are a couple of links with some instructions to get started on uninstalling your antivirus.
both links are getting a little aged, so take a look. If you have trouble getting specific uninstalls to function, let me know and I will try to do a write up specifically for it.