Call of Duty 2 runs perfectly well on single player - I have the system specs, I have the latest video drivers, etc. When I access the Multiplayer part of CoD 2, however, I encounter some difficulty. I can get a list of servers to appear, but when I double click to join the game, I am met with an error which reads something like "Error reading Key code, please input key code for verification". The first time I tried Multiplayer, I had not entered the key code in the "Verify Key Code" area (in the Options menu for Multiplayer, I think), so initially I wasn't surprised to see such an error message. So, I inputed the code and verified it (the game said it was a valid code), but when I attempted to join a game, again it gave me that error message. I looked at the "Verify Key Code" area again and for some reason, only the last four digits of my code appeared. I entered the full code again, verified it, and tried to join a game, but the problem persisted.
Ok, so it seemed like the game was unable to remember the key code. I then went in search of a patch, which I found (on the official site) and uploaded. When I tried to install the patch, however, it told me that it could not find any version of Call of Duty 2 on my computer. Alas, I was still unable to join multiplayer games (though, it should be noted that I can make my own server).
This got me thinking - maybe the problem with my multiplayer has something to do with my computer not recognizing that Call of Duty 2 has been installed. Since I have encountered a similar problem with "The Movies" (also produced by Activision, strangely enough) - which, in brief, greys out the "Play" option whenever I put in the first CD and prompts me to install the game...which I already have installed - I suspect there might be a serious problem with my system.
So, my question (aside from the obvious "WHAT SHOULD I DO???") is: what would cause a computer to not recognize that a game/program has been installed?
Any help would be much appreciated.