LO opens Writer

Whenever I try to open Calc, following an upgrade to, Writer opens instead. This happens if I select the Calc entry from the Start menu (Win 7 x64) or if I try to run Calc directly via Windows Explorer (c:\program files(x86)>LibreOffice4>program>scalc.exe). It then becomes necessary to use Writer’s File > Open to select the appropriate spreadsheet, which then opens normally in Calc, and I can then shut down the unwanted Writer.

If I open a spreadsheet directly from Windows Explorer, Calc opens normally. Whilst the above relates to my desktop PC, I have the same problem on a laptop running Win 8.1 x64

Suggestions please…

Have you considered uninstalling than reinstalling the program? Couldn’t hurt.