Only m$'s security essentials will run on server 2008 (r2) and is also free. As far as I know, you are allowed to use it in commercial environments for up to 10 PC's. On 2011 servers it no longer works. The other free AV utilities you can only run on desktop OS's, not server OS's, and you are only allowed to use them on private PC's (not PC's used in companies). Clamav is an OpenSource and free AV tool you can use on as many PC's you want, also on company PC's, but it has one large disadvantage.

Drop Patch L2 Interlude Client there. Dell Latitude Fn Key Driver. The Windows version doesn't do automatic on-access scans, so you have to manually scan every new file, and run system scans regularly. This means you aren't automatically protected like with the other AV utilities, and it requires lots of discipline on the sides of the users to be of any use.

Microsoft Windows Server 2008 R2 64-Bit. Windows server 2008 r2 download iso full version free download. AVG AntiVirus for Mac.

It does support Server 2008 (r2). I've installed it and it is running on my 2008 r2 servers.

But as I mentioned above, it won't run on the newer servers (2012 and above) anymore. One other thing, m$ security essentials is mainly meant for PC's running XP, and m$ has guaranteed that it'll keep on getting updates for at least one more year. I'm not sure what exactly that means, maybe after that it will be dropped completely, also for higher OS's. So possibly next year you may have to replace it with another AV utility. Besides that, the free version of Avast!, like so many other free AV versions won't install to a server OS's, but rather only to Desktop OS's, so they aren't really an option.

One thing you could also consider though, if this is just a trial environment, is to use commercial trial AV software. As far as I know most of them allow you to download, install and test their software for a trial period for free. Just don't ever get anything from Symantec, as all their stuff isn't much better than malware!