while opening any excel files (.xls files) in MS EXCEL.EXE, I need to do
some data existence check in that xls file. How do I do this. Can anybody
shares the brief details.
i.e. The user can open any xls file in EXCEL.EXE and my addin/application
should work in back ground and look for the existence of particular type of
data (specific data pattern) then update some [m,n] cell on the xls file with
YES/ NO values etc.,

I tried developing COM Addin using C# but could not get the corresponding
event for opening the exisitng workbook.

Any help would be great and appreciated.

I am using OFFICE 2003 and Visual Studio .Net 2003 on FrameWork v1.1

thanks,
-Ram.