Hi im using Ubuntu 12.10 x64 Desktop and successfully connected using putty then i used command # vncserver after gen password using tightvnc viewer i successfully logged in and can get my Desktop i tested xclock its working after i changed : -root password -create user 'oracle' -edited visudo and addred root permission to user 'oracle' -reload ssh -logged in as a oracle now xclock not working "Error: Can't open display: " as a root also getting same error echo $DISPLAY not shown anything please help me to solve this error i like to use GUI insulation Thanks -suresh