IF statement using Dcount - Rookie user

Here is the code

If DCount("[Serial Number]", "INVENTORY OVERVIEW", "[Serial Number] =" & Val(txtSERIAL)) > 1 Then

Serial Number is the field I'm trying to count INVENTORY OVERVIEW is the table where I am trying to do the count txtSerial is the text box on a userform

The objective of this if statement is to determine if there are more than one of the same serial number, and report to the user when they submit a new entry if that serial number already exists within the recordset.