Black screen or possible hang after sleeping or locking

After my laptop locks the screen (not always), or after sleeping (pretty much always), I'll go to log in but it seems to have hung or is not responding. The screen is backlit, no cursor shows at all and nothing I do will make it come to life. It knows I'm back, but entering my password blindly, or switching tty's back and forth does not seem to make a difference. I can only force shut down holding the power button. I have it set to shut down when power is momentarily pressed, but this does not seem to shut it down either... Force shutoff only works. I am running KDE but this was also happening when running Gnome a wee while ago. It seems related to Debian/lappy, not the desktop... Thoughts?