Can't run as Admin

Question

I have to execute the ewfmgr.exe which can be executed only when the Command window is opened as an Admin.

If I go to Start->type cmd.exe

Answer 1

I'd like to point to an NSIS specific way about dealing with UAC and elevated rights.

If your NSIS installer needs to run anything with elevated permissions, you have to indicate that in your NSIS script like so:

RequestExecutionLevel admin

Once you do that, when you start the installer, it will pop up the UAC prompt and in succession won't have any problems running external scripts or programs which need elevated permissions.

This is pretty much in line with #5 of Mofi's answer - I still post this one as I think it boils it down to the need-to-know. NSIS seems to be the show-stopper here for you.

For reference: NSIS - Could not write updated PATH to HKLM