OMFG, I've never seen so many threads about the installation error!
If you have an error messege like this after you install 2142 demo:

Solution A:
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This is how you fix the d3dx9_29.dll installation error:
Download this---->DirectX Updater!
Install it.
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Solution B:
If that doesn't work, click here and download this file.
After it get done downloading, unzip it and move the file to this location: C:\windows\system32
If you need more than the "29" file, they can be found on that site.
If there are any more issues with the install, notify me with the problem and the solution, and I will post it here.
If you have an error messege like this after you install 2142 demo:

Solution A:
-----------------------------------------------------------------------------------------------------------------------------
This is how you fix the d3dx9_29.dll installation error:
Download this---->DirectX Updater!
Install it.
-----------------------------------------------------------------------------------------------------------------------------
Solution B:
If that doesn't work, click here and download this file.
After it get done downloading, unzip it and move the file to this location: C:\windows\system32
If you need more than the "29" file, they can be found on that site.
If there are any more issues with the install, notify me with the problem and the solution, and I will post it here.