The computer enters sleep/hibernate and then exits. Why?

Question

Windows

A computer on an Asus Z87-C motherboard, Windows 7 OS. It enters Sleep / hibernate, waits there for 2 seconds, and then immediately exits.
What's the matter?

Answer 1

Most likely the network card wakes up the computer. Try disabling the permission to wake your computer from sleep.
Device Manager -> Network Adapter -> Power Management -> uncheck "Allow the computer to wake up from standby"