Do I need separate virus protection for Virtual PC running in Windows 7?

I just switched from XP to Windows 7 Pro, and because I’ve got a Personal Information Manager that I like a lot (DeskTop Set), I downloaded and installed Virtual PC and XP Mode.
The first time I opened Virtual PC, in the Virtual PC Window there was the little red shield “Windows Security Alerts.” I clicked it and got the Windows Security Center window which indicated that I had no virus protection. I had just downloaded and installed MS Security on Win 7. I have no experience with virtual PCs, so… what gives?
Do I have to treat this virtual PC like a completely separate computer? I won’t be going online with it, but I’m not sure that will protect me.
Thanks,
Mac

 

Yes you should treat it like a completely separate computer.

That being said, if you completely disable the network adapters in the XP Virtual Machine then you will be ok. as far as network threats are concerned. You can still get viruses from any infected files that you put on the XP VM.