After messing with Bios a little (but hopefully putting everything back as it were), and running CPU stress test on http://silver.urih.com/
my computer won't go out of "Sleep" (standby) state. It starts to go out, power goes on, but the fan's remain noisy as they always are in the moment of power coming on, and then nothing appears on screen. After a while when I tried to press reset button, I got 3 beeps from motherboard, so I power down PC by long press. I cold booted, put PC in Sleep, and when resumed, same thing. But I didn't wait for the beep this time.
Is it possible that it is related to BIOS settings? I have ASUS Bios. What else can it be?