Think I have a Virus, how to get rid of it...?

I just came online this morning and almost everytime I go to a new website an AD pops up on my computer. And in the bottom right corner a little thing comes up and says "Ad by BrowsingSoftware".

I have already tried:

to look for it in

-Add/remove programs and its not listed there.

And have tried:

-AVG Free Edition

-SpyBot: Search and Destroy

-Nortons AntiVirus (my main virus protection Software)

Now when I click on the bottom of my site where it says

-Add ons currently installed in Internet Explorer on the bottom of my screen, it shows up there and I disabled it. But it is still popping up.

Any help greatly apprieicated.

Can anyone help please. I

Think I have a Virus, how to get rid of it...?vista

DON'T GET NORTON.NORTON TRULY SUCKS,AND IT'S OVERRATED!IT SLOWS YOUR COMPUTER DOWN,AND IT ISN'T THAT GOOD!

Trust me,when I tell you the best ones to get are SuperAntiSpyware,Ad-Aware,and The Ccleaner.They are free,and they are both really good.You can also try AVG.It's pretty good.Please try these.

I would also get the McAfee Site Advisor,because it warns users when downloading software or filling out forms on a web site that may make them victims of malware or spam.

http://www.superantispyware.com/

http://www.siteadvisor.com/

http://www.filehippo.com/download_cclean...