Like, I have TEXTBOX1 and i enter a number that already exists within TABLE1. I would like it to pop a message up "This number already exists" and would keep doing so untill i enter a number that doesnt exsit.
You want to use the beforeupdate event for this. That way you can cancel the update if the number is found. I would use the Dlookup or DCount functions to query the table to see if the number exists.