I am required to design a course schedule that covers a year. I have pretty
much finished except for creating a formular that will prevent names being
used twice between certain dates. I have set out the worksheet as follows;

Column A Column B Column C Column D Column E
Start Date Finish Date Course Manager Senior Inst Facilitators

I have created lists of names in drop down boxes for each position and have
found part of the possible formular in a previous post for discounting names
that have already been used and is as follows;

'Suppose that you have your list from A1 to A10, from the Data menu choose
validation and from Allow drop down list choose CUSTOM and in the formula bar
put this:

=Countif($A$1:$A$10,A1)=1'


Thanks for your help in advance.