Adding Shutdown rights for users in Windows Server 2008 R2
Normal users don't have permission to shutdown a Windows Server 2008 server.
Permissions can be granted by an administrator by doing the following...
Open the Security Settings configuration tool by either
Running the Local Group Policy Editor (gpedit.msc) and navigating to Computer Configuration > Windows Settings > Security Settings, or
Going directly there from Administration Tools > Local Security Policy.
Navigate to Local Policies > User Rights Assignment and add the user/group to the Shut down the system policy.