im having multiplayer issues

[Puzz3D]

Open Start
Click Run
Type: regedit
Go to: "HKEY_LOCAL_MACHINE/SOFTWARE/SEGA/Medieval II Total War"

You'll see a value representing the CD-key. Change it to what it should be.

-Don't type spaces
-Do type the "-"
-Don't use "O" use "0" (zero)
-Type everything except for the numbers in capital letters

Save and exit. Don't make a mistake editing the registry because that can mess up Windows. It is possible to backup the registry before you edit it.