How do I get rid of this School filther block from my personal laptop.?

My youtube usage has been blocked by a message connected with "8e6 R3000" . When I upgraded AVG 2009 Free edition to AVG 2011 I ran into this block but I am not sure now if AVG is the problem because I uninstalled AVG 2011 along with Google Chrome. Fortiguard messages whould sometimes popup before this but now youtube is totally blocked. I found out that "https" can get me part of the way to a video but the video displays a message " an error has occured please try again later" . School policy is great for kids but I am 57yrs old. How did I become infected with this policy on my personal computer? Do I have to reinstall my OS?