Sophos Antivirus wont open and I have virus attack / threat

Hi Guys can anyone enlighten me please.

My other laptop on switch on gives an virus threat message of

Threat MAL/FakeAvHm-A

Threat source

http://www.google.co.uk/search?

Sourceid=navclient&ie=UTF-8&rlz=1T4TSEG_enGB356GB360&q=sophos

The request location contained malicious content and was blocked from downloading.

Any ideas of what it is?, How serious it is? and how I can get sophos AV to start, to sort it out.

Cheers