unable to access Microsoft store

good evening,

I have been trying to gain access to my Microsoft Store account, and I am being asked to enter a pin. When I enter the pin that I believe to be the correct one, the system informs me that I have to try again. I then enter forgot pin and when I attempt to reset the pin it asks me for my business account which I do not have a business account. I have a new computer for my Teenage son and I am trying to access games through the store that were already purchased. Please help