I am watching your beginner lessons and it repeatedly states that Primary Keys and Auto Numbers are used as a means of creating unique identifers that do not duplicate.  I am using Access 2010 and inputting data but noticed that the Auto Number has started duplicating numbers about 100 numbers off where it should be (for example, I am inputting entry 2248 but the auto number that is created is 2144).  Did I not set my primary key correctly?  Can I reassign an auto number?  I have been completely baffled by this and unable to fix it.