I just built a new pc and when i left home today, the monitor went into sleep mode but when i got home, the mouse or keyboard would not wake it up. I tried pressing the power button because it is set up to shut down via power button but that would not wake or shutdown gracefully either. I had to hold the power button for 5 seconds to shut it down. When i turned it on it was normal of course with the not properly shutdown sign, and when i tested sleep mode again, everything was fine and sleep mode and wake mode worked normally.
Specs: i5 3570k cpu, antec 620w psu, gigabyte z77-ds3h mobo, 500 gb wd hardrive, 8 gigs of ram, and gigabyte hd 7870 gpu. Can anyone tell me why it only did this one time and the rest not. I only built this comp 2 weeks ago. Forgot to mention that the pc was not set to sleep mode only the monitor was.