Web pages being hijacked

Hi Diana,
I recommend start with uninstalling all unknown/unused programs and browser addons.
Thanks

Hi.  I downloaded the free trial of AVG Antivirus today and ran a scan - it removed some problems I've been having (thanks).  My main problem is that every page I try to view online (with the exceptions of FB, my Yahoo mail account, and this page) is highjacked by the following URL:   http://www.platformdll.com/flv/au/index.html?sid=2124&dv1=ad2121-au&kw1=ad2121-au-cl&uuid=68d65bc2-0ac7-4910-444d-fb7ae22095dc   This prevents me from browsing and, basically, from using the internet for anything other than reading emails and FB posts.  The page that takes over claims that I don't have an up to date version of Adobe Flash Player, but I do.  How do I stop this website from hijacking the pages that I want to view?  It's a really frustrating problem and is making my internet experience miserable. I don't want to buy AVG AntiVirus until I'm sure it can help with the problem. Thanks.

Hi Diana,
I recommend start with uninstalling all unknown/unused programs and browser addons.
Thanks