In order to make the VNC program run as another user you can do either of the 2 following options:
 
1)      Click Start > All Programs > Ultra VNC and hold down the Shift key while right-clicking on the Ultra VNC Viewer icon
Now you can choose the Run as different user option and enter the credentials
 2)      This second method uses a shortcut on the desktop:
 Right-click an empty area on the desktop > New > Shortcut
When prompted to enter the location of the item enter the following:
                C:\Windows\System32\runas.exe /savecred /user:kimconnect\*** "C:\Program Files\UltraVNC\vncviewer.exe"
                (you will replace the *** with the username of the desired user)
Click Next
Give it a name (ex- VNC)
Click Finish
 
Now when you double-click the icon it should run with the credentials entered