• Press the Windows Key + R and type msconfig into the run dialog that pops up.
• Click on the “Tools” tab and scroll down and click once on the “Disable UAC” option.
• Click the “Launch” button.
• Close the CMD window that pops up and close msconfig
• Save your work and then reboot.
  
  

This security feature which Windows Vista implements is a virtual “blanket” between a standard user account and an administrator account. This leads to a more secure system because administrator level tasks, such as modifying the registry or installing new programs, cannot be done through a normal user. As a result, Vista will prompt you whenever you run any program which tries to perform this action.

This popup usually dims the screen and halts all activity until you answer. While this is a good security measure, you might want to disable it if it inhibits your usage. Here is how:

For Vista Business and Ultimate:

1. Open Control Panel (Classic View).
2. Open Administrative Tools.
3. Open Local Security Policy.
4. Select Local Policies > Security Options.
5. Locate the option for “User Account Control: Behavior of the elevation prompt for administrators in Admin Approval Mode”.
6. Change this value to: Elevate without prompting.

 For Vista Home versions:

1. Open Start > Run > regedit
2. Go to: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
3. Change the value of ConsentPromptBehaviorAdmin to 00000000
4. Close regedit.
   
   Source: http://www.pcmech.com/article/category/tips/