I'm playing through the old CoD games and recently finished the first one. When I was uninstalling it I ran into an error so I had to remove it manually (deleting all files and registry entries I could find related to it.) However it appeared that the original has to be installed in order to play United Offensive, but now that I try to reinstall CoD it believes that it is still installed! Hitting "Uninstall" in the menu does nothing (is starts an installer process but nothing pops up) and trying to launch Single Player just gives me an error. Any clever ideas on how to bypass this?
Try using Revo Uninstaller, have used it in the past for programs that wont come off properly. http://www.majorgeeks.com/Revo_Uninstaller_d5706.html
I've had this problem in the past. Insert the CD, browse the disc directory, find and run install.exe - that should do it.