My computer has a flashing icon that brings up pop ups,?

how do i get it off of my computer,and it also has ads poping up trying to get me to purchase internet security

My computer has a flashing icon that brings up pop ups,?virus scanner

Sounds very much like your computer is infected with the Zlob Trojan. Zlob Trojan generates 'Critical System Alert' messages and tries to force you into buying rogue antispyware products. To remove these message and the trojan that generates them, download and scan your PC with SpyNoMore, it is the most accurate program in detecting zlob infections.

http://www.spynomore.com/trojan-zlob.htm

By the way it is not free, but then again you should really question any so-called free solution. Isn't that how your computer got infected in the first place?!. The free scan will only check your system and show you the infections. If you choose to remove them, be prepared to pay.

My computer has a flashing icon that brings up pop ups,?anti virus software

run a ful system scan, then let norton anit virus delete it

then it will put the computer back to it,s orginal congifuration.
Run your antivirus and any spyware removal programs you have, if that doesn't get rid of it go to http://noahdfear.geekstogo.com/ and follow the instructions to remove it
Excellent suggestion above, ones that I would have made myself. I would like to add that you should download Mozilla Firefox, it's much better at security...IE7 is just a catch-up copy of Mozilla.
try spybot - this works pretty good - your isp should also have some type of spyware remover