"Floating" foreign data in my spreadsheet.

I have a spreadsheet I have been using for years. Recently data from a web search I was doing, outside Excel, on the Internet in dictionary.com, somehow imposed itself on this Excel spreadsheet. {I do not recall if the spreadsheet was open in another window at the time or not, I think it was.}
I have been able to get rid of all else that appeared on the spreadsheet. BUT, I cannot erase a box with the capitalized word “SEARCH” in it or move it or even "touch" the box with the word SEARCH in it. My cursor passes right underneath the box with the word SEARCH in it, like this box was a bridge over water.
If I type where the box is, I can see what I type, until I press enter. Then, if the SEARCH box covers part of the cell, I can see the uncovered part of what I just typed. If the SEARCH box completely covers the cell, when I press enter, the data then disappears under the boxed-enclosed word SEARCH.
I need an EXCEL EXORCIST to tell me how to excise this "devil" box. I have been using Excel for about 24 years and this is wholly new to me and unsolveable. HELP please ! Murf