From what I know about this problem, it seems to be caused by the installation of some additional software that creates a false pointer to the path you mentioned above. The path
C:\Program Files\Microsoft is not a default path.
My advice would be to download Autoruns from Microsoft and check the entries under:
This is one of the locations that auto-start programs store their entries. Take a look at the entries listed there and and one by one uncheck the box to the left and restart; try to establish if it's one of these entries that's responsible. Once you know which are responsible, you can re-enable the others.
I wouldn't simply advise leaving the responsible entry unchecked, without doing some research on exactly what it's responsible for. It may be important...