F11 also works in IE to go to Full Screen or to toggle it off.
If that doesn't work, you can often get your Start bar to move to the front and become accessible by hitting the special Windows key on most PC keyboards made post-Windows 95. You should then be able to right-click on the tab that pertains to the window (or anything else that's open) and use the right-click context menu to "Close" the offending window.
By clicking on the User Name, you will requery the forum for that user. You will see everything that he or she has posted with that Mudcat name.
By clicking on the Thread Name, you will be sent to the Forum on that thread as if you selected it from the main Mudcat Forum page.
By clicking on the Subject, you will also go to the thread as if you selected it from the original Forum page, but also go directly to that particular message.
By clicking on the Date (Posted), you will dig out every message posted that day.
sj