If I set my Windows Updates to download automatically at 2.00 am in middle of night do I have to leave the computer switched on, or will the updates be carried out with the computer switch Off but not at Mains ?
The computer would have to be switched on and connected to the internet to receive any Updates. It is much safer to pay a regular visit to 'Windows Update' which can be found at the top of your 'All Programs' list.