"Is your anti virus set to check your hard disk at a certain time?"
No that fires up much later in the morning at 8am. Moreover no programs are running when the incident occurs
"Is the monitor turning on or the computer booting up?"
The monitor is turning on, its waking up from the sleep mode it goes into as if someone moved the mouse.
"Just a thought,
Check your BIOS most new MB have a "Wake on LAN (or ethernet, whatever!)" function, and your internet connection may use an ethernet port? so any activity on your connection could possibly wake the computer up...
Some high speed connections periodicly check their status with the server etc,.."
I am using an ethernet port for my LAN, which is connected to the internet via a cable router. I needed no special software to run this connection so I wouldn't think my NIC is doing anything out of the ordinary, any outside influence trying to ping my machine would run into my firewall (zone alarm, which is in a stealth type mode) and I would get a pop up notification for blocked traffic (which I have not).