Norton keeps resetting my home page to symantec

I got norton as a 90 trial on a new PC.  If this keeps happening I am quit certain that I will not countinue with norton.  I thought norton was supposed to stop programs from changing my home page, instead it is the problem.  I'm not going anywhere different with this computer that I didn't go to with my old computer and no virus or adware is being found so why does norton keep changing my home page to www.symantec.com?

 

edit:

Vista Home 64bit sp1. 

I have no idea which norton product it is and can't figure out where to look for that.

It doesn't happen all the time, just about once a week or so.

Message Edited by volkner on 01-19-2009 09:21 PM