Using the command line, try these to find out what's causing it:
powercfg -lastwake
That should tell you the source of the wake command.
powercfg -devicequery wake_armed
That one should tell you which devices are set to wake the system, similar to looking at the power options for every device in device manager.
powercfg -waketimers
That one will tell you which, if any, programs have wake timers configured.
Powercfg is a really useful cmd line tool in these situations. :-)
Last edited by Tonka777; 8th May 2015 at 12:22.