Boots up automatically
Try in the Bios, disabling WOL (Wake on Lan)
http://en.wikipedia.org/wiki/Wake-o...
http://en.wikipedia.org/wiki/BIOS
Most modern ATX motherboards should have a 3-pin Wake-on-LAN connector near the PCI slots and should included BIOS support for Wake-on-LAN power up. If you have an Award BIOS check the Power Management Setup for this option.