Why won't my Calculator turn on?

One day I was using my calculator (while plugged into an outlet) and I put it down for a little bit and came back about an hour later and my calculator wouldn't turn back on (still plugged in). I've tried the whole taking out the battery thing and I tried the whole holding down on, EE, shift or whatever but I spent a decent amount of money on this (no warrranty) and I need it for math quite terribly.