To whip your Kindle into shape as an auxillary PC display, tap the Kindle’s aA button and reorient the screen so that it is horizontal (like your computer monitor).
Make sure that TightVNC Server is still running on the computer – you will be connecting to it in a moment.
Using your Telnet client (PuTTY or your app of choice), send the commands highlighted in bold below:
If everything proceeds correctly, your Kindle should look like this
Your account will be closed and all data will be permanently deleted and cannot be recovered. Are you sure?