In Vista UAC (User Access Control) is both anoying and can prevent you for doing some tasks remotely. For example, Installing Trend Micro Client Security Agent is not possible over VNC if UAC is enabled. UAC will cause a window to pop up asking you to confirm that the drivers that the antivirus is trying to install are legitimate. When UAC is invoked you will often lose VNC to a computer, I found that this a very common issue when installing drivers in particular. In looking for a easy way to disable UAC on a few computers while doing some maintenance I found this command line chunk.
Disable UAC:
Enable UAC:
Note that in Vista though this can be run from command line but if you make it a batch file you will have to right click and select ‘run as administrator’