Microsoft Excel - ctrl+shift+up arrow keys not working

Can macros affect the normal  behavior of ctrl+shift+up arrow keys

Yes, it's possible to override the default behavior of any key or keychord by using the Application.OnKey method from VBA.

I'm only posting because I hope that I'm wrong, but I can't seem to be able to use Application.Onkey to override Excel 2007's built-in alt key shortcuts.  I would really like to be able to customize my own alt key shortcuts to macros.  And I don't want to have to press more than one key after Alt (I know 2007 will let me do that.)

You could override menu accelerator Alt keychords by using the OnKey method if you first changed the Caption property of the menu.  E.g.:

Private Sub Workbook_Open()
  ActiveMenuBar.Menus(4).Caption = "Insert"
  Application.OnKey "%i", "module1.MyAltIprocedure"
End Sub

Private Sub Workbook_BeforeClose(Cancel As Boolean)
  Application.OnKey "%i"
  ActiveMenuBar.Menus(4).Caption = "&Insert"
End Sub

Now that Excel 2007 intercepts those keychords as "Office 2003 access keys," I don't know how to disable their interception; I'm afraid it's hard-coded, and not as an event.