I have something on the PC which redirects my searches to weird sites, I can't actually click a Google link from a search without it sending me off to something completely irrelevant.
As well as malwarebytes, download and run Spybot Search and Destroy (free) from http://www.safer-networking.org
, then in this order:
1. update it
2. run the Immunize tool
3. run the Search and Destroy tool and click "Check for problems"
Then uninstall whatever anti-virus you are using and install Microsoft Security Essentials (google it) and you're good to go.