Quick one this, Microsoft have finally entered the security software arena with a
completely free, lightweight, quiet, tidy anti-virus and malware
package called, catch-ily, “Security Essentials”.

It has received generally excellent reviews and is the first Security product I have ever run.  I urge everyone to download and install it, unless you are a die-hard user of one of the paid-for packages, and arguably even then?

This won’t be part of automatic Windows Update for a long while as
the big anti-virus companies still carry enough clout to make rumbles
about anti-competitive behaviour.

So download it from here: http://www.microsoft.com/Security_Essentials/

I recommend removing any other anti-virus package from your PC first, especially if it’s a free one (AVG etc).