I have just figured out how to set my Media Center PC so that I can turn it off to standby (to RAM) and back on again by the remote, but the problem is it keeps turning itself back on overnight

I have disabled all the wake-up on LAN etc in the bios, and can't find any scheduled tasks that might be waking it up? It doesn't have a mouse or keyboard plugged in (except the Media Center Infa red remote and keyboard) so it can't be that...

I have also left it on in the day for 4 hours or so and it hasn't come back on.

I'm stumped!