I think BIOS has options for turning on by USB or some other devices.
You could attach some kind of one button keyboard and from Windows to make ONLY it wake the pc.
Device manager has that Option in the device Properties --> Power Management --> Allow this device to wake...
EDIT: If you want...
I have an Acer Aspire V5-531 laptop. Runs games like WoW at about 30 fps at semi-low. Also BFBC2 Lowest 720p 20 fps, just for comparing. It costs ~400€ And don't even think about high WoW in this patch O.o
So my BIOS hasn't got the "Advanced" tab... How can I unlock it so I can assign more memory to my integrated graphics card?
Also my pc model: Acer Aspire V5-531