I’ve been having some problems trying to enable UAC and spent some time trying to resolve this, starting a technet post to help. My preference would be to use Group Policy (GPO) to enable this, however experienced issues with the UAC not being fully functional (no admin elevation prompts). Unfortunately I never really got to the bottom of the issue., however as a workaround used the following script in a *.bat file to disable it in the registry.

Enable UAC (via *.bat)

%windir%\System32\reg.exe ADD HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System /v EnableLUA /t REG_DWORD /d 1 /f

Disable UAC (via *.bat)

%windir%\System32\reg.exe ADD HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System /v EnableLUA /t REG_DWORD /d 0 /f

Problems with GPO (technet):  Enable UAC via GPO | Windows 7