Laptop m1730 sleeps when lid is closed and does not respond when lid is opened

I have set my power settings so that the laptop goes to sleep when the lid is closed, and it does as told. However, when i open the lid it should wake up? you can hear the disk start spinning, but the monitor does not turn on and so nothing else is happening.. I have tried hitting every key, even closing the lid again but it wont go back to sleep. I end up having to hold down the power button to shut it off.

any suggestions??