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 Sniper Elite V2, make sure everything installed smoothly.
Exit Steam entirely.
Browse to your Sniper Elite V2 installation folder (Usually C:\Program files\Steam\Steamapps\common\sniper elite v2\)
Run the following installers:
Reboot your computer and test any issues again. If the issue persists, contact Sniper Elite V2 support.
Downloadable content will not be listed as a separate entry in your Steam games list. When purchased, this content will be automatically downloaded and incorporated into the game.
Additional content for Sniper Elite V2, including the "Kill Hitler" mission, can be found under "Single Player" in the main menu.
From here click on the "Challenge" menu.
You will then need to change the game mode option at the top of the screen to "DLC".
You can then cycle through your DLC and make a selection by clicking on the left or right indicators below.
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: