A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Like others have pointed out, one has to start closing out programs one by one until they stop getting the annoying pop-ups, and it could differ depending on the PC.
At my job, we don't have Skype. We do use Microsoft Lync and it was the first thing I signed out of and closed down... bang, no more clipboard problems. I got lucky, it was the first thing I tried closing.