Thanks for all the responses. The problem did happen in safe mode as well.
I came up clean after deep scanning for viruses & spy/malware. I took the
suggestion of starting IE without add-ons first and it worked fine. Seems
to also have fixed the problem with Adobe Reader that started just before the
multi window problem - I installed Reader 8 and every time I'd open IE7 Adobe
would pop up a message that it "could not open the file" before I even tried
opening anything and when I did try would give me another message and not
open the file.

Thanks again for the help.

Jo