WHen I was using the calculator, the computing button was on the screen for a long time (all I was asking hp to do was to do a simple division). SO, I went on to take the battery out and put it back. Then, the screen turns to a full black scrren with the computing sign on there. I do not know now to fix it. The calculator just do not turn on or off or cancel!! Pls help me out, apprecipated.

Carmela

Hey there, you might try doing a machine reset through the reset button on the back of the machine. I believe it is under the upper-right rubber foot. You will need a paper clip to press the button through the small hole. You need to hold it down for approximately one second. The batteries need to be in for this operation. If that doesn't work you can try leaving the batteries out for a couple of days. If that doesn't work I am out of ideas.