Windows 7 'toolbar' Is Partly Hidden

I suddenly discovered my windows toolbar was partly hidden - this means that the 'save' file icon in excel has disappeared completely.
My taskbar, at the top of the screen, looks normal size, what I call the windows toolbar is just a thin strip making it impossible to switch between tabs for certain apps eg excel. one copy of IE11, but not Firefox, not my other copy of IE11 how to restore it ? Note this means I cannot see minimize, maximise or close tab buttons ! it must be just one or two buttons....

Dumb_Question
25.September.2019

 

yes it was something simple, a few buttons or just one, don't know which though, something to do with f11 full screen, maybe
wish I could delete this question

 

I didn't know that; I knew only that Alt+Tab cycled through your open windows (or something like that). This isn't / wasn't related to issue, which if not solved, has gone away.
Thank you for your attention, plodr

Dumb_Question
28.September.2019