Mirar is sort of adware, this is what a web search brings up;
Mirar Toolbar is a toolbar addon for internet explorer. It has the ability to hide, and then re-emerge, making removal difficult and very annoying. Mirar attempts to find Web pages that are related to the Web page currently being viewed. It also displays advertisements based on the URLs and search terms used while navigating the Internet. It will also attempt to download and install the Mirar toolbar from a predetermined Web site.
This will tell you how to remove it
It's not an easy or quick process though your best bet would be to install a spyware protection program