Shut Down Doesn't Always

Used my laptop earlier today, sitting on the desk and plugged in. Walked away from it. Came back four hours or so later. White light on the front was on, but no other indications of life. Nothing wakes it up. Tapped the keyboard, tapped the pad, closed then reopened the lid, tapped the power switch. Nothing. Only way to wake it up is to hold the power button down until the light goes out (maybe 6 seconds?) then tap the power switch and let it power on as if it had been turned off. This happens frequently.

This morning I clicked the black apple in the upper-left-hand corner of the screen and chose "sleep". Upon returning a half hour later I was unable to revive the computer. I tried clicking the mouse pad, tapping the power switch and closing and opening the lid. The light in the front of the laptop was on continuously throughout. I finally held down the power switch until the light went out, then tapped the power switch to turn the computer back on. Came back on OK but all my applications had closed and many were giving me the "sorry we closed unexpectedly" type message. Very similar to the closing-the-lid problem that happens occasionally.

And...45 minutes of work gone. Nice.

Interesting. I just clicked the black apple and chose to restart the computer. It just went to the enternal spinning gear, just like it does with shutdown. Finally held down the power button for several seconds then restarted. This can't be normal.