ERROR: No assistant installed on opening the program

[Samrcat]

I am now getting the same warning as others that at least one assistant must
be installed. They are installed.

I have done the control panel add/delete program and REPAIRED my office
program. I have tried to ADD new features from the add/delete program area
too. I have gone into Excel and chose the detect and repair. I have even
rebooted my machine and tried again. What is the "MAINTENANCE mode" and how
do I get this back? Assistance would be greatly appreciated!

-Samantha