My Android tablet is asking for a PIN which I do not have a clue as to what it is can you help me ?

Personal Identification Number. We sure don't now yours. Did you set up your account? If not, you need to do so.

Have you activated any new features like perental control or anything that controls downloading apps? Often times devices want you to set up a number so if your children get ahold of it then they can't just buy everything under the sun.