If UAC is blacking out your screen…

For Vista Home Users:
Type in regedit in the start menu search box and press Enter. Browse to the following registry key:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System]
Double-click the key called PromptOnSecureDesktop and change it’s value to 0.

For Vista Business and Ultimate Users:
Type in security in the start menu search box. Click on “Local Security Policy” and browse down to Local Policies \ Security Options. On the right window, scroll down and find “User Account Control: Switch to the secure desktop when prompting for elevation”. Double-click it and change it to disabled then click OK.