Help with software and OS version compatibility for a new, circa. 2000-2005, Virtual Machine

I wanted to reinstall some old software that originally was designed to run on Windows XP 32-bit. Figuring I could also run Coldfusion 4.x through MX 7 (this is something I have reasons for wanting to do—I don't need to be advised to install newer server, thanks), I created a virtual machine and installed Windows XP. All would be fine, except that XP only allows for the creation of one web site under IIS 5.1, and I need to run more than one. So, it's back to the provervial drawing board for me.

So, I'm shopping for a new Windows OS. In a Windows help forum where this one web site under IIS issue was discussed, someone suggested installing Windows Server 2003. This gets me off into the weeds.

My main concern is that, at some point, my other software, created to run on Wind XP, started getting really funky under new OS's. I bought this software new in 2002, and I kept it through a few PC and OS upgrades. It definitely didn't like Windows 7 Pro, at all. Would run, but with errors, and the help system was dead. Having it run solidly was why I went back to Win XP.

The question I think I'm asking is which Windows OS's will agreeably run software written for Win XP 32-bit, will provide multiple web sites under IIS, and will also run CF server from 4.x through MX? Trying to research these issues leads to all sorts of bunny trails.

Thanks so much!
John