IF YOUR GAME WON'T EVEN START UP and you bought a german retail version or EU-Version, try setting the language to german (or appropiate language) via Steam (Library->Metro 2033->Properties->language). Steam will then re-download about 2.1GB and after that the problem should be solved (if you already have installed latest graphics/physx-drivers of course). Don't be afraid, that the game itself will be in german then, it won't. text and speech stay english.
IF YOU HAVE TROUBLE SETTING YOUR DESIRED RESOLUTION, because your screen goes black and maybe you get a message "out of range" or something similar, you can easily configure resoultuion and refresh rate (this is a problem due to the game using a refresh rate your monitor can't handle) through the game's config-files + adding a startup-command in Steam.
To do this you only have to look for the TWO user.cfg-files. In Windows 7 they are located in: <drive letter>:\...\Steam\Steamapps\Common\Metro 2033\
C:\Users\%username%\AppData\Local\4A Games\Metro 2033
You want to find and change the following lines (best in both .cfg-files):
Now you have to add a startup-command for this game in steam. Go to "Library->Metro2033-Properties-Set Launch Options....". There you add the line "-refresh 70" without the exclamation marks (or whatever refresh rate you'd like/need to have for the game).
YOU ALSO MAY WANT TO CHANGE THE FOV-value to an appropiate one for yor aspect ratio respectively resolution. The standardvalue is 45, I changed it to 78 which is a good value for 5:4 aspect ratio. You may change it through this line:
To look which FOV is good/best for you, you can use this calculator:http://www.rjdown.co.uk/projects/bfbc2/fovcalculator.php
If someone else likes to add solutions for other or similar problems, you are cordially invited to scribble them down here :).