2

Open a terminal (Ctrl+Alt+T) then run:
crontab -e
If it asks you to select an editor, choose nano. Insert these lines at the end of the file:
0 3 * * * vboxmanage controlvm virtualpbx acpipowerbutton
5 3 * * * vboxmanage startvm virtualpbx -type headless
Press Ctrl+O,Return to save the fi...