In Windows 7, you can change the User Account Control (UAC) setting via the User Accounts applet in the Control Panel. However, if you’re looking for the registry setting, here it is:
Hive: HKLM
Key: \Software\Microsoft\Windows\CurrentVersion\Policies\System
DWORD Name: EnableLUA
DWORD Value: 0 = Disable UAC, 1=Enable UAC