can not insert object
 

Command buttons which previously worked OK on worksheets now do nothing when
I click them. If I try to add a new command button to a worksheet I get the
error message 'can not insert object'. This happened before and some how I
generated an Excel error which asked if I wanted to report the error to
Microsoft. I said Yes and I got a reply that the error had a solution from
Microsoft. I downloaded the fix, which I can't remember what it was, and the
problem went away. This morning the problem came back. Does anyone know
what causes this and what the fix is.
Thanks.