...and if after unplugging all USB devices, plug them back in one at a time, and see if the computer will start itself. If nothing happens, unplug that device and plug in the next one. Plug, wait, unplug in this fashion with all of the unplugged devices. If one of those devices is the problem, it should cause the computer to start when it's plugged back into the computer.
If something gets your goat, it just proves you have a goat to get.