I am getting some very strange behavior when using Excel. Two things are happening (i) I am getting a "Save As" dialog box when I did not request one, then Windows keeps popping up new boxes even after I close them, and (ii) within Excel I am getting a proiferation of worksheets named Chart1, Chart2, Chart3, . . . . ."
I am afraid this could be a virus or a worm of some sort.
In case anyone sees similar behavior, the problem was a stuck key on the keyboard of the computer in question, so there was an easy fix with no harm done.