Show that if G is a group of order 4 then either G is isomorphic to the cyclic group Z4 of order 4, or x^(2)=1 for all x in G.
I have got this far....
For two groups to be isomorphic they must have the same order, be cyclic and be abelian.
Case 1: G is cyclic (and abelian) therefore is isomorphic to the cyclic group Z4
Case 2: G is not cyclic (not abelian)............therefore x^(2)=1 for all x in G.
I don't understand the connection between the group not being cyclic or abelian and the condition x^(2)=1.
Please help, thanks.