Registry: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System

Setting this value to 0 allows administrators to perform operations that require elevation without the respective annoying popup prompt.

Setting EnableLUA to 0 (zero) disables User Account Control (UAC), that is, users are not prompted for a confirmation when a program is about to perform an operation that requires administrator privileges.

This key is called EnableLUA because User Access Control was previously called Limited User Account (LUA).

The following cmd.exe batch file sets the value to zero and thus diables UAC:

@reg add HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System /t REG_DWORD /v EnableLUA /d 0 /f 1>nul