Question : msgbox displays if serial number in table

when you open this database you will see form with one button on it.
you click button and enter serial number.
form is based on query of two tables.
I have a 3rd table called tblDestroyed.
After I enter serial number, and click button.
I want an msgbox to display if the serial number is also in tblDestroyed and say something like "This is a damaged part".
is this possible
A Serial number that is in both tables -is  9NLJ45-
if you enter that I want the msgbox to display.
thank you-(database attached)
You will see I tried an example expert gave me and am doing something wrong - giving me error - thought i had it working

Attachments:

Join221.mdb (260 KB) (File Type Details) 

two tables- error

Answer : msgbox displays if serial number in table

Give this a go

Regards