locking workbooks
 

I have a program that may need regular updating, but is used by other members
within the company. They need to use the program everyday, but is there a way
of locking the program so they can not delete or add to the program, but
access can still be obtain by a certain user. The program needs to be stored
in the same directory (so read only is a no go), so only one person can use
the program at any one time. The main point is that the other members of the
company no when the program is being updated and CAN NOT AT ALL access the
program.