Toggle Between 2 Windows

[Aria]

Hello,
I have a separate working file that I'd like to paste into a finalized
budget file. I think a macro would work great but my macro records the
specific file name whereas I'd rather have the paste-to file name be
based on whatever file is currently opened within the Window. I'll just
toggle to the finalized file that's already opened and do a paste. I'll
ensure that there will only be 2 files opened before activating this
macro. Could somebody please help me with this? Also, what's the code
for ending a macro simply by clicking on the corner "X" in the
messagebox?

Dim curWks As Worksheet
Set curWks = ActiveSheet

'msgbox ({name of the current file} will be pasted to {other window's
file name}, _
vbYesNo, "Move Information")
If vbYes Then
'if paste-to file doesn't contain a Secondary Budget tab, then msgbox _
({other window's file name} doesn't contain a Secondary Budget
tab. Paste _
can not be done). exit sub

curWks.Activate
Cells.Select
Selection.Copy
Windows("Budget 2007.xls").Activate
Sheets("Secondary Budget").Visible = True
Sheets("Secondary Budget").Select
ActiveWindow.FreezePanes = False
Range("A1").Select
ActiveSheet.Paste
ActiveWindow.SelectedSheets.Visible = False
Sheets("Primary Budget").Select
curWks.Activate
Range("A1").Select
Application.CutCopyMode = False
Windows("Budget 2007.xls").Activate
End If

End Sub

Aria

 

[Aria]

Please help. This command will open a file. But on the second time I
activate this command, it errors on me because the file is already open
(thus, I don't need the prompt for choosing a filename). How do you
switch to the file that's already open without the error message?

Dim file1 as string, wkbk as Workbook
file1 = Application.GetOpenFilename
Set wkbk = Workbooks.Open(File1)

Aria