Do anti virus downloads like Avast prevent virus' or just detect and clear the?

What anti virus, anti spyware, anti IM software can I get (free or otherwise) to prevent attack when my PC is clean?

Do anti virus downloads like Avast prevent virus' or just detect and clear the?avast

dont no if the free norton scan gives u all time protection u can get norton from www.argos.co.uk or www.pcworld.co.uk it stops viruses spyware from getting on your comp its 25pound for a year....

Do anti virus downloads like Avast prevent virus' or just detect and clear the?ducati

Go to http://www.download.com/PC-Starter-Kit/2...
i use "AVG". it really is good and can be downloaded free.
Don't understand what you mean by anti-IM software. If you don't want to use chat software then don't install it... Some anti-virus programs do protect IM programs like Yahoo Messenger and MSN Messenger but it's typically a feature you have to pay for.

Anyway, as for free versions, the feature you want to be looking for is something called "real-time scanning". That means that when you try and open a file that can hypothetically carry a virus, the anti-virus software checks it out first (very quickly) and either allows it to open or tells you it's infected.

Not many free anti-virus programs have that facility but AVG Free Edition does. It ain't a pretty program but it does the job.