I just completed a HTPC build consiting of a small ITX form factor case and ASUS CPU/Mobo ITX combo. All I have plugged in is a USB keyboard, mouse, and ethernet (well then of course the HDMI cable to my TV).
I have the power settings set so when I push the power button the PC goes to SLEEP. Problem is in the morning I usually wake up to the thing turned back on.
No other power saving features have been customized other than the "choose what the power button does" and the rest is set to the Windows default "Balanced" power features.
When I push the power button it's usually to go to bed so the mouse and keyboard are undisturbed during the night.
I've scoured the settings and I cannot find anything that may cause the machine to wake up unannounced.
Windows 7 x64