Okay,
Virtual CD drives are common, but you should know if you have one or more installed on your computer, unless there is a more computer savay person also using the computer. Anyhow.
Go to Start menu(bottomleftcorner), then >> control panel, then >> System
In the system window click on the Tab at the top that says "Hardware" and device manager should be there. click it.
in there is a list of all hardware that is installed or detected on your computer.
Look for your CD or DVD drives. If there is more than one there then you have one or two CD drives, then disable all the other ones not in use. DO this by rightclicking and selecting disable, you may have to reboot, disable all before you reboot, but leave the CD drive you are going to run the game on..
PS.
the install disk for the northamerican release is the play disk ive heard too.
Hope this helps, the game rocks so far, I cant wait for my first nuclear war!
~Schella~