If Form2 exists, it will never be nothing.

There are a couple ways to do this
1. When Form2 loads, have it set a public variable either in your main form or in a bas module & reset it when it unloads
2. Add this to your Form2
Code:
Public isLoaded As Boolean

Private Sub Form_Load()
    isLoaded = True
End Sub
Private Sub Form_Unload(Cancel As Integer)
    isLoaded = False
End Sub

' Now from any code, you can check via:  Form2.isLoaded = True