VS 2008 closing a form

I have a application that has three forms, form A, the main form, form B and form C. On form's B and C I have a button that allows me to close that form and show the main form A, and the code I Have below has worked for a long time, but now all the sudden it closes that form, either B or C like it should, but then it completely closes out the application verses displaying the main form. I tried switching the order of these two lines, but that did not work.

A.Show()
Me.Close()