I have a Windows Server 2012 VPS, don't want to run my own hardware 24/7
Microsoft Security Essentials seems not work (official statement from MS) or it is not supported!
And there is just a lot of buying Software.
So I try BitDefender Free even if it seems not supportet (official) as well.
It's just for my demo account for a real EA Test under live conditions with MT4
The only gate for the virus is the remote desktop, firewall and the MT4. IMHO the antivirus will not do better job than the up-to-date firewall.
I recommend to ask first to your VPS provider, your system is running as a virtual machine on a server, ask them which software you can install without break it.
More than antivirus you need: firewall and maybe anti-malware.
the vps provider called me. he says it belongs to what you are doing with your vps.
you need a antivirus if you receive documents p.e. if you run an email server.
in this case he recommend software from MS.
if you don't change documents or files you don't need a antivirus system.
the agent don't know about mt4 but in my words i would say for a only mt4 installation it's not necessary