You could use Data - Validation - Custom - =G17<TIMEVALUE("16:45:00")
placed in Cell G18. You will want to change the error message to let the
user know why data entry in G18 is not valid.
--
HTH...

Jim Thomlinson


"Katherine R" wrote:

I'm a novice using Office 2003. If the value in cell G17 is greater than or
equal to 4:45 PM, I would like cell G18 to be locked to prevent an entry.
Can this be done?