Hi Tinman. It's very simple. Rename your existing CFS root directory folder to any other name. Then insert the CD & install in the usual way. You will now have 2 separate installs of CFS1 that will run independently. You can run the original from a shortcut to Combatfs.exe pasted to your desktop.

Providing you have enough spare HD space you can do this as many times as you wish. I once had 4 "duplicate" installs of CFS1 & 3 of CFS2. As you play online I think the latest install will be the master & the one recognised on the Zone.