Having been recetly "bit" by UAC and the server needing a reboot to disable it, I thought I would do a refresh on how to disable UAC.
UAC is an attempt to control the level of access that a user has over protected applications or processes on a server. This article shows the method to disable UAC. If you need to leave UAC enabled but modify the default behavior there are a couple of links at the bottom.

Windows 2008

When you receive the below pop-up, UAC is turned on.

To disable this pop-up, there are a couple of different methods. The most reliable method to completely disable UAC is a via changes to the registry.
1. Launch regedit and navigate to:
HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System
The default value is : "EnableLUA" = dword:00000001.
Change this default to: "EnableLUA" = dword:00000000.
2. Close regedit
3. Reboot the system
If you want to use the GUI to disable UAC navigate to:
Start - Control Panel - User Accounts


Un-check the radio box "Use User Account Control (UAC) to help protect your computer"
Reboot the server.

Windows 2008 R2

The registry edit to disable UAC on a Windows 2008 R2 server is the same as for Windows 2008.
1. Launch regedit and navigate to:
HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System
The default value is : "EnableLUA" = dword:00000001.
Change this default to: "EnableLUA" = dword:00000000.
2. Close regedit
3. Reboot the system
To use the gui, follow this path
Start? Control Panel ?User Accounts
The Windows 2008 R2 UAC uses a "slider" to disable the UAC.

For more information on UAC and to make adjustments rather than just disabling there are a couple of Microsoft links listed below: http://technet.microsoft.com/en-us/library/cc709691(WS.10).aspx http://technet.microsoft.com/en-us/library/dd759070.aspx