if the laptop lid is closed it enters sleep on no battery when i noticed it would lockup upon resume being a black screen or the "locked" screen with cursor disabled and nothing responding with the power light green as if it resumed normally which only a reboot would resolve. 99% related to the...
battery
black screen
dellusers
emachine
freezing
hibernation
laptop
lockup
power management
resume problems
sleep issue
tech support
troubleshooting
wake on usb
windows 7
