You computers motherboard has to support this feature. Read motherboard manual!
This is how i enable this feature.
  1. Restart your computer
  2. Enter BIOS
    (Read motherboard manual if you dont know how to enter BIOS)
  3. Go to tab "Power"
  4. Go to "Power Up Control" and press ENTER
  5. Go to PS2KB (PS2 - keyboard) Wake up from S3/S4/S5 and press Enter.
    Select start key(s).
  6. Go to PS2MS (PS2 - Mouse) Wake up from S3/S4/S5 and press Enter.
    Select Enable. Press Enter
  7. Press F10 to save and quit.