Do this:
You will need 1 Original DVD for the Main game and 1 Original DVD for the Addon to get this work. Other it WONT! (At least from what I know. I won't try it an illegal way)
To prevent to get Auto Defeated after 3.30 mins while playing LAN, do the following: (You can also try to install normaly, but to be 100% sure do the following:)
If games are still installed, then deinstall the games in this order: Mod (if you installed any), then BFME 2 - ROTWK and last BFME 2.
Be sure you deleted all folder regarding to BFME 2 + ROTWK. Look for yourself in your installation paths!
Now use CCleaner (just type it in google, pretty helpful tool you shouldn't miss anyway) and clean your registry AND computer.
Now shut down your Windows.
Start computer and tap "F8" constantly until you get on a black screen which lets you choose to "start Windows in safe mode" (abgesicherter Modus).
After choosing this option Windows will start after a few minutes. Now install BFME 2.
If the Disc doess't start automatically go into "round windows symbol on the left side", then "computer", then double click the DVD drive where your Disc is in.
After installing don't start the game and continue with installing BFME 2 - ROTWK, you won't start that game also.
Now Install the 2 Patches.
Then Install Daemon Tolls Lite (dont use other Version of it)
Insert BFME 2 Disc but close the autorun.
Start Daemon Tools Lite and click on "create an Image".
Choose your DVD Drive on which your BFME 2 Disc is in. (example "G:") and click on start.
Do the same for ROTWK Addon.
After it is finished, start the "BfME Startup Fixxer.exe".
Now mount the Images with Daemon Tools and take the game discs out of your DVD drive.
Now go and try if it worked.
Took me 1 and a half day to figure this out... It was a mess. I had the game running already. But while playing LAN I got game.dat crashes and hope reinstall would fix. But only installing without safe mode on WIN 7 somehow killed the CD KEY installation it seems. So I installed in safe mode and all cool, no not all still got game.dat crashes sometimes. But at least it worked after 1 and half full days of trying stuff lol