superuser do for Windows

Using a Limited account during your everyday work protects you from malicious software infection and
accidental misconfiguration. But installing software or changing some system settings can be difficult
in a low privileged environment.

 The sudoWn project can execute individual programs (or even a whole Windows shell) with temporary
Administrator privileges under your user profile. This means you can use a low privileged environment and
elevate your rights transitionally for software installation or systemwide configuration comfortably

http://sudown.mine.nu/