Shut it down completely and do a normal, cold boot - you may have to hold the power button down for several seconds to fully power it off. If you get the "Please wait" again, give it a couple of minutes.
If this doesn't work and your laptop has a removable battery, then power the computer off, pull the charger and the battery out, press and hold the power button for 5 seconds, and then reconnect power and try again.