Having worked in a large enterprise, it's common place to never keep using a system which has had a virus infection- it's just too risky to keep using a system which has once been infected. There's simply no quick fast easy way for an enterprise to check what damage a virus may have done- even after 'removal' a virus may have re-created itself into another form which is not detectable to the current virus scanner (this is known as ' Polymorphic code' which changes itself every time it runs making it much harder for virus scanners to detect. So what can be done? Well as with the common cold- the first and best steps are prevention. This is the primary role of you're firewall to try to prevent known attacks from reaching your computers inside your network. A few well revered free firewalls for windows include:
> ClamAv
> Comodo Firewall & Internet security
> Avast internet security
> ZoneAlarm
Both Comodo and Avast also offer complete free internet security suites with antivirus, firewall and spyware protection.
There's little functional difference between the two (given they are both in competition with each other) so it's really a matter of preference- which one is easiest enough for you and is the least distraction?
Avast, although free, still requires you to register yearly for a licence key- so they get your email address.
Comodo doesn't have this restriction and therefore has the 'convenience factor'. Give both a try, remembering not to run both at the same time- unfortunately antivirus products generally do not play well together!
Distraction is a key point here. Everybody hates frequent popups from security programs asking "do you want to allow this program to run?". Thankfully, this is becoming behaviour of the past. Today many security products are able to automatically make this decision for you when it recognises well known, trusted, applications.
The non-free McAfee antivirus suit has told us it used it's own network of customers to 'learn' common safe applications and aggregates this to decide if the programs on your computer are safe to run.
Free solutions such as ClamAv also employ this strategy, albeit in a less automated fashion, by a community of submitters who submit unknown applications and files to the central database inspection. It's also true that free antivirus products do in fact outperform commercial products sometimes, killing the argument that you are safer with a commercial solution.
In conclusion, beware of claims saying your always better protected with a commercial antivirus- this simply isn't the case.
Instead, focus on identifying a solution which is the least distracting to you.
