Excel filters lock up

Filters on my Excel spreadsheets keep "locking up". That is, I can no longer click in the cell with the filter drop down. When this happens, I've noticed that the row #'s on the left are black instead of blue. My only solution is to remove the filters, unhide all rows, and reapply the filter. I have to unhide all rows, because when I remove the filter, I find that whatever rows were hidden by the filter remain hidden. I reinstalled Office, and even now have a new PC and the problem has followed me. I send others the same spreadsheets and they don't have the problem. I create brand new spreadsheets and the same thing happens. Makes no sense to me.