VS 2008 Easy Way To 'hide' All Other Open Windows

I just created an idle lockout screen for my software (it's financial software, so if the program is inactive for 5 minutes, the login screen appears again).My question is... is there an easy way to hide all the other windows in my program that may be open? So let's say they are in frmData, and they have the dlgOptions screen open, with the dlgOptions_SelectItems dialog open from dlgOptions. There are 2 dialogs open on top of frmData. And, they are all opened with .ShowDialog().So, let's say they have that many windows open, and then leave there computer for 10 minutes. After 5 minutes, the login screen appears. But all that other stuff is in the background.Is there an easy way to "hide" all the other open windows, and just show the login screen, and then once login returns DialogResult.Yes, then show the forms/dialogs again? I could do this by delcaring instances of each form in a main module and doing it this way. But that sounds like a pain in the butt. Also, I don't know If I could hide frmMain while a dialog is open from it.