In the Project Navigator, select the first sheet, then scroll down and "Shift-Double Click" on the last sheet. That should open up all of the pages.
You can then use the Window > Close All to close them all at one time.
Thanks Rick. I was pretty sure I had read something once that told how to do this, I just couldn't remember what it was.
Thanks for replying. Now, if somebody (like me) searches, they should find this thread