Thats for XP and all that will do is make the activation dialog show activated, its the value from which OOBE reads its days left (aesthetic)
In Windows 7 WGA has been renamed to Windows Activation Technologies and is a little different than the previous versions of WGA so a simple reg change isn't going to work right. If someone has a pira*ed version then most likely they are using a BIOS mod or loader which activates the OS thus no need to bypass WAT. If you do not want to run a loader or modded bios then look into a strictly files based "fix" in Hazars RemoveWAT Late