Vista - Internet search returns bad results...how do I fix it?

For the past few weeks, I've noticed that when I do a search, Google, MSN
etc...I get the page of suggested sites pertaining to my subject. When I
select one that most nearly fits my needs, I end up on pages about all kinds
of unrelated stuff. Frequently it is also very vulgar pages that return (and
sometimes I have to turn off the pc because I can not close them.) When I hit
the back button, instead of taking me back to the page I selected from, I
land on another entirely different page. Now, If I perform the search and
instead of selecting the item, I copy the address into the web address field,
I get the correct page. What causes this and how do I correct it? I have
WindowsXPPro, I run Norton, Webroot Spysweeper and Spybot.
Please help..
--
SMC

Clear your browser's cache

"SpareMomentCreations" <SpareMomentCreations@xxxxxx>
wrote in message news:20B0992C-EF95-490E-8F77-35DB3946AE5B@xxxxxxYou're infested with some sort of malware. Do a Google search for "Hijack
This"

Sample hit: http://www.whatthetech.com/hijackthis/

Follow the instructions and submit the log to an appropriate forum (not
here!).