Originally Posted by lordrahmo
There is a problem that cause Deus Ex - HR to fail to load under windows 8
Events prior to the issue
will happen if you have installed and run Deus Ex under your old OS (say windows 7) and then updated to windows 8.
The resulting problem
is that when you run Deus Ex it asks is you want to play or set-up but both options actual do nothing.
Verify the Deus Ex install in steam then run the game this will reinstall the direct X package you are missing and the game will then run fine. Alternately I believe installing ANY other steam game will also fix this.
Steam installs some direct X files every time a game is run for the first time (if you have lots of steam games you are sure to be sick of seeing it do this). Well those files don't come across in the upgraded to windows 8 so they need to be reinstalled.
I posted this here in the hopes that it can help others get this (or I think ANY other steam game running). It would be great if this could get a sticky so that it can save as many people as possible from this issue (alternately I am happy for this fix to be copied where ever it will help, [credit for working it out would be nice if you copy it[)
Many thanks for sharing this solution. It has been added to updates on first page.