Just to let you know guys, I have also got the game running in software mode (it doesn't look too different than D3D to be honest!) in my XP using win95 compatibility and using a CPU speed controller (freeware) called SpeedSwitch XP. It is actually designed for laptops to save battery life by slowing CPU speed. I got it to work after turning on my Cool'n'Quiet option in my Bios (Award). What it does (on my PC) is take my dual core 2.8ghz down to two 1.0ghz, I then switch one off and therefore now have a 1.0ghz CPU. I used this program to get 'Outcast' running, and thought i'd try it with W&W. So if getting a win98 disk for Virtual PC is not possible, try downloading SpeedSwitch XP. I have an AMD CPU, so I downloaded 'AMDClock' which allows me to quickly see CPU speed. This is how I know SpeedSwitch XP takes my cpu's down from 2800 to 1000 on each core!
I hope you have cool'n'quiet (or similar) on your motherboard and that SpeedSwitch XP works on your PC (just double clcik desktop shortcut then right-click on taskbar icon and choose 'Maximum Battery'- it's that simple!) as it does mine, because you then maybe be able to get the game running in either D3D or software. I can only get it working in software with it, but you may do better, and it's a better answer than finding a Win98 OS disk!
