- Install xming
 - Set up putty, use x forwarding, diplay loc localhost:0.0, rest is default
 - Start xming
 - On centos:
 
yum install xorg-x11-fonts* libXtst xorg-x11-xauth xorg-server xclock
Test using xclock. If $DISPLAY is not set you did it wrong. You can also test mobaxterm, it works well.