Months ago I was infected with a virus that prevented AVG and MBAM from running. A friend ran MBAM from a flash drive(I think), which got AVG and MBAM back working on the PC.
Some time later, I noticed Windows Update no longer worked and Google searches were occasionally being redirected. Clicking a second time on the search item always worked. I didn't realise until recently that these may also be symptoms of the virus.
Then Malwarebytes AntiRootkit got Windows Update going again. I also ran some of the other tools mentioned here but I still get Google redirects.
I'd appreciate advice on what to do next.
I use Windows 7 Home Premium and Firefox.