Redirect virus???

When I boot up I get my home page address in the address window, but it immediately goes to another address.  First it was going to prize winning site, then later a quiz taking site, now it is a pornographic site with nude pictures on the screen.

 

I have Norton Security 2012 and it does not find this in a scan.  I have tried Norton Power Eraser to no avail. I have also tried TDSSKiller and today I scanned with Pro- something or other that was mentioned in the forums.

 

What do I need to get rid of this annoyance?

 

JD