The community is also a great place to check out. Try these places for help from other users:
If you're encountering issues with launching Total War: Shogun 2, make sure everything installed smoothly.
Exit Steam entirely.
Browse to your Total War: SHOGUN 2 installation folder (Usually C:\Program Files\Steam\steamapps\common\total war shogun 2\)
Run the following installers:
Reboot your computer and test any issues again.
Fall of the Samurai can be accessed from the single player menu in Total War: Shogun 2. In order to access Fall of the Samurai please do the following:
Note: Owners of Fall of the Samurai only will see only "Total War: Shogun 2" listed in their Steam Library. The Fall of the Samurai campaign can be accessed using the instructions above.
Steam DLC is automatically downloaded and integrated with your game. You can get a list of the content that you own by right-clicking on Total War: Shogun 2 in your Steam library and selecting "View downloadable content."
If you are still having trouble locating or accessing DLC that you have purchased, contact Shogun 2 support for detailed instructions.
If the above does not resolve the issue and you are running Windows 7 or Windows Vista, please complete the instructions in our Windows 7 and Vista Troubleshooting FAQ.
If you are running in Windows XP, take the following steps: