I just made a small text change and when I selected a new page that message came up and continues to spin saying
"Cleaning code and history stack"

It's been about 5 minutes so far. Wondering how long I should wait or is this a fatal message.

This is an old site, on a PC, using Version 2.5 Build 2425

That shouldn't take so long unless it is a HUGE site
I would try closing (save if possible) then reopen

But hang on to your hat, it might be that the project has gotten corrupted (hope you made a back up copy

Yes, I made a backup just before the last changes so I have that. I just tried shutting it down and reopening and it was fine as far as I can tell.

When I tried to open my backup it wanted to open in a later version so I made another copy and let it and selected the Foundation option. It also seems in fine shape. Now I think I will copy that version and bring it to my iMac and see if it behaves. Wish me luck!
C

Hope all goes well