Studio 1558 won't wake from sleep mode unless I press power button

My husband and I have the same identical laptops. His wakes from sleep mode by pressing a button on the keyboard or moving the mouse.  Mine does not.  I can only wake it by pressing the power button.  I have reset to default power settings and it still doesn't work.  I have gone through keyboard properties and have found nothing that says anything about sleep or wake.  The power button wires have severed (which is normal for this junky laptop, or so I hear) and so in order to turn it on and off, I have to press the wires together.  In order to avoid doing this often, I wanted to put my computer in sleep mode and be able to wake it up with the keyboard.  But, as mentioned above, I am unable to.