This is simple guide for all the known issues of the game (that I know about) that I mangaed to find.

P.S. Only doing this part to make the guide look nicer :P

All updates I make will be written here.

1. Making the guide, includes:
1.1 - Single Player not working (general protection failed...).
1.2 - Retail CD Key not working on Steam.
1.3 - Multiplayer Issue

2. Added:
1. How To Change Language.

If you're encountering issues when launching or playing Medal of Honor, make sure everything installed correctly.

Aside from verifying your game cache and checking your connection with Steam, you may also need to manually run secondary installers required by this game.

Exit Steam entirely.

Browse to your Medal of Honor installation folder (Usually C:\Program Files\Steam\steamapps\common\medal of honor\)

Run the following installers:

...\Steam\Steamapps\common\medal of honor\install\redistributable\vc8redist.exe

...\Steam\Steamapps\common\medal of honor\install\redistributable\vcredist.exe

...\Steam\Steamapps\common\medal of honor\install\PunkBuster\pbsvc_moh.exe

...\Steam\Steamapps\common\medal of honor\install\PhysX\PhysX_9.09.0408_SystemSoftware.exe

Reboot your computer and test the issue again.

If it doesnt work, please tell me cause it worked for me and thats the problem I had!

The reason the Retail CD Key doesnt work for you on steam, is becaues its not ment to work on steam.

Retail CD-Keys for this game cannot be registered through Steam. If you wish to create a shortcut to this game under your Library instructions can be found here:
Adding non-Steam games to your Library

If you are having difficulty launching and authenticating your Multiplayer key, download and launch the Single Player portion of the game and get to the main menu. Once this is complete, you may exit the Single Player and attempt to launch the Multiplayer portion once more.

Additionally, you can view your CD Key for this game by right-clicking on your "Medal of Honor(TM) Single Player" Library entry and selecting "View Game CD Key."

If there are more issues with the multyplayer, please comment and I will try and find a fix for them.

There is a bug where some people cant manually install or fix PhysX through the said file in the above fix. WELL! A Fix to the unfixable fix has been found!
Simply go to your Control Panel and enter Programs and Features. In it click on the Nvidia/NV PhysX icon and select repair and there you have it!! It should be working now!

Thank you NoStall for finding this fix!

This one is actully very easy, all you need to do is this:

1. Go to your Steam games library.
2. Right click Medal of Honor (TM) Single Player / Multiplayer.
3. Click on properties.
4. Click on the language tab.
5. Select the language you want.
6. Enjoy :D

Thank you very much for reading! I hope I helped you fix your problem! This is my first guide so tell me what I can do better with my next ones!

If there are issues I didnt write about please comment bellow and I will try to find a fix for them and if you already know about a bug I didnt write about and you know how to fix it, please tell me and I will add it in the guide and give you credits for it!

Hope I helped!
~Bruce™