My computer will go into the Sleep mode after a certain amount of inactivity. How do I turn of the timer on that function? The real problem is that when this occurs it locks up the system and I have to use the external Start button to close down the computer. The same thing occurs if I click on the Sleep button or Shut Down. I have a fairly new Compaq Presario w/512 RAM and 2.2Ghz speed. Is this a software or a hardware problem.