How to lock or unlock cells based on values in another cell in Excel without VBA

[trimiii]

Hello everyone... I need help. I have an excel sheet that I need to lock cell-based two values in another cell.

Row A1:A7 - I have days, Monday- Sunday
Row B1:b7 - I need to enter working hours, for example, 8 hr
Row C1; C7 - because of Friday and Saturday is day off, I want to lock this column and not to allow the end-user to enter any number.


I figure out how to do with one criterion but need help to combine the formula.

Steps that I am following:
selecting cell C1
use ribbon "data validation"
Select custom and enter formula example: =C1="Friday" and it works but I need to add on the same cell the command for Saturday as well.

Any idea.

 

[johnnyL]

= OR(C1 = "Friday",C1 = "Saturday")