I’ve been running dual boot Windows 7 and Windows Server 2008 R2 on my laptop for a little while now. I use Windows 2008 R2 for running Hyper-V guests for testing and demo purposes. For some time I’d been running Microsoft Security Essentials on the Windows 7 partition, but without any Anti-Malware software on the 2008 R2 partition – something that made me a little uncomfortable. Recently, I found Comodo Antivirus. It’s free and seems to run quite happily on my Windows Server 2008 R2 partition.
Be aware that it does throw up the occasional advertisement bubble from its location in the notification area of the Windows task bar. This doesn’t really bother me – it seems a small price to pay for peace of mind.