End If, Exit Sub problem

Here is my code:Private Sub Image2_Click()

If Sheets("customer").Range("C3") = 0 Then
MsgBox "You Must enter a Customer Name"
Range("C3").Select
End If

If Sheets("customer").Range("C5") = 0 Then
MsgBox "You Must enter a Store Name"
Range("C5").Select
End If

If Sheets("customer").Range("C7") = 0 Then
MsgBox "You Must enter an Address"
Range("C7").Select
End If

If OptionButton1 = True Then
Sheets("relamp_codes").Select
End If
If OptionButton2 = True Then
Sheets("retrofit_codes").Select
End If
If OptionButton3 = True Then
Sheets("relamp_codes").Select
End If

End Sub

What I want to do is after each MSgBox error, return to the sheet to correct the error then continue on to the next if statement. The way it is written, the code continues on without requiring the correction. If i use an exit sub, the code stops?
What am I missing?
Thanks.