Once you turn it on, how does it turn off? Does it go into hibernate or stand by mode? and what do you have it do when the lid closed? I ask because I had a Dell Latitude C series that would do that but it was a bug with how the system handled power options like stand by and hibernate. It would never recover from lid closing going to standby mode and would sometimes not come out of hibernate. Pressing the power button would do nothing and I had to unplug it and remove the battery to get the power button to work and power it back on. I think a BIOS update fixed the problem. I also would make sure APM/ACPI is enabled in the BIOS and Windows sees it as that type of computer since that's what controls all that stuff. Also review your settings in the Power Options Settings like what happens when the lid closes and what does it do when the power button is pressed. Some have this set to go to standby but if there is a problem with it returning from standby then change that to power off the system. I have mine (Dell D550) set to power off when the power button is pressed and do nothing when the lid closes and then sleep when the sleep button is pressed (which I never use).