well you have to be using firefox browser for one
because they have a built into the browser pop up ad blocker...
or you can easily download it as a add on...
next you need to identify the >exe file that's running that script...
you can usually see it under the task manager
under the processes running tab
we can look it up on google easily enough
http://www.2-spyware.com/remove-antivirus-2009.html