Hi mate,I'm no expert but always looking for something better and having a good tutor I have picked a few things up which might be able to help others.My mate worked in a computer repair shop for quite a while and I was allowed behind the scenes as to say, I was surprised at the amount of computers that came in absolutely riddled with various rubbish .The lads in the repairs dept always blamed the anti virus which came with the computer for being too nosey and looking for thing that aren't there that caused most of the problems.The lad now works from home and advises people to use Avast or AVG,I have always used Avast with no problems,fingers crossed.Both are free downloads,NEVER have two or more anti viruses running on your computer.Timmo put me onto a free anti spyware , Super anti spyware.I l also do a complete scan with this once a week (at least).Be careful which sites you visit some are noted for viruses.If you are not sure when you get a pop up or taken to a site you didn't log on to hit the red button top right of page DO NOT open anything you don't understand.
http://www.avast.com/eng/avast_4_home.html
http://free.avg.com/gb-en/homepage
http://www.superantispyware.com/?tag=GOOGLE-SUPERANTISPYWARE
and here's another site that I like to use,I find the cc cleaner very good.
http://www.filehippo.com/
This lot is just my opinion and not the bible.
Lindsay