get this message every time i try to play cod2, iv clicked yes and no but all it does is go back to steam!

how to play multiplayer without needing hour of downloading and not adding weird stuff to the game menus

I copied steam.dll and steam2.dll to the cod2 folder, now the game turns off by itself, there is a black screen for a while and then returns to the desktop, turning off the game, I tried using the single player, but the message appeared in the game "CoD2_MP needs more permissions" I made both files compatible sp3, I set the administrator run, still nothing, I restarted the PC and now it throws me to the desktop again ;(, I tried the shortcut to desktop, nothing either. PLEASE HELP...

I tried all possible fixes posted online, changed the compatibility etc, even fiddled with the microphone settings for some reason but the campaign still has a black screen always whenever I start it. Multiplayer however works fine which puzzles me. Anyone facing the same issue ?...

is it easy to get a game going?