So you have decided to change antivirus software on your computer or get rid of that awful trial version , here is what you should do.
Remember you need to make sure you thoroughly remove your current anti virus on your computer.
Your anti-virus solution can be uninstalled from the Programs section in your Control Panel however some remnants may remain so you should go to the manufacturers site and look for a removal tool which will remove all remnants of the software and that you should be aware that some antivirus solutions will not let you uninstall them now unless you use the removal tool.
I have included some links below for popular anti virus solutions.
After removal reboot and proceed to install your new anti-virus solution.