Windows 7: Antivirus for small office

Hello,
I would like to ask you for an advice for an antivirus software for a small office (3-4 PCs XP/Seven).

At home I've been always using AVG Free and I think I cannot use the free edition in an office, can I ? I had a look at the price of the non-free edition and there is a yearly fee which has to be paid which I don't really like. Is this command the there is a year license for antivirus software ? Which other antivirus would you recommend ?

Thanks for your help,

Tex

If you can wait a few more days, you can use the free Microsoft Security Essentials for up to 10 PCs in a business environment.

Announcing: Microsoft Security Essentials available FREE to Small Businesses in October! - Microsoft Partner SMB Community Blog - By Eric Ligman - Site Home - MSDN Blogs

I can wait but I've just tried MS Essentials and the 1st problem is that I cannot update the virus definition when I'm behind a proxy. This doesn't really gives a good impression of the software. Maybe will they release a new version in October which is more business friendly ..

Updating behind proxies has long been a problem and not just for MSE either.

See the 4th post down here as it may help you: How I can update MSE via proxy?

It always is useful to do a Google Search on the subject.