If by "keeps on beeping", you mean a continuous tone, then my vote for best answer is that one of the keys is stuck. Swipe your hand back and forth gently across the keys several times...all of them.. look for one that feels "low" ...see if you can convince it to rise with gentle taps or strokes and then try it again.
If the beep is a single beep and then later, say 10-30 seconds, it beeps again, endlessly repeating, then the next best answers is a hardware failure, in which case you'll probably need more help than an FR post.