These images show the first time you run the msi file…
The last image, is the error message I get when its almost done installing.
Btw… this msi file is only 55 MB ? Is that normal ?
Regards,
Plorax.
“Key not valid for use in specified state.” is the error message as can be seen in the attached image.
Yes, that is normal, because you are just installing the launcher -> when you have installed the launcher you can download the engine 
For your problem:
I have never seen this error before but:
Make sure that you have full admin rights on your pc. Otherwise it could also be caused by a windows update ://uhesse/2014/08/31/windows-7-error-key-not-valid-for-use-in-specified-state/
You are the man! That fixed it!
Thank you very much you oh so kind sir 