Following Microsoft KB instruction (http://support.microsoft.com/kb/304662), it is easy to embed an excel workbook (spreadsheet) in a .Net Winform program.

The real problem arises when there is a stand-along Excel application already running before launching an Excel-embedded Winform. The stand-along Excel application will hang up. It is believed that the Winform will take control of the external Excel instance. If more than one stand-along Excel instances are running, then the first one will be taken over by this Winform.

All Visual studio .Net versions have the same problem. Microsoft just totally ignored this obvious issue. Does anyone have a good idea on this problem? We have a not-so-elegant workaround for it. But I am looking for a better solution. Thank very much for your help.