Multiple Servers on one Dedicateed Box

[Wandering_Jesus_freak]

Hello,
From what I understand, I can run two servers on a single machine as long as I use a different port and have the horspower/bandwidth. My questions are:
a) Am I correct in the above assumption?
b) Do I have to use a VM (which take sup a bunch of resources) or can I just make it run in a different folder?
c) the following specs will work (the server also runs my home file sharing network)?

AMD Phenom II x4 925 (2.8 Ghz)
16 GB RAM
Windows Server 2008 R2 64 bit
10000RPM WD Raptor Sata HD


Thanks!

[Nisd]

a: Yes (Just give them like 5 ports of space, Server1: 27015 - Server2: 27020, and so on)
b: No (No need for a VM)
c: We also needs to see your bandwidth, but depending of size and such I would say you are good for 4x20 slots, according to your CPU.