Microsoft has added a new feature "User Account Control (UAC)" in Windows Vista and Windows 7 which is a good addition. It prevents malicious programs to install in your system as well as it also prevents basic users to accidentally change system critical settings which can be harmful to the system.
Although its a good feature but sometimes it becomes annoying to experienced users who know what they are doing with their system. So if you also find UAC prompts annoying, then here is a very small but excellent utility "UAC Tweak" made by our friend "Tom" which can easily turn off UAC or can set the UAC settings to High, Medium, Low so that you get less annoying UAC prompts.
As you can see in the above screenshots, you can choose any desired option and it'll apply it immediately. Restart your system to take affect.