I just use
Set dbs = CurrentDb
dbs.Execute "Update [table] set columnA = valueA, columnB = ValueB Where ColumnC = ValueC;"
If dbs.RecordsAffected = 0 Then
dbs.Execute "INSERT INTO [table] (columnA, columnB, columnC) VALUES (valueA, ValueB, ValueC);"
Else
End IF
It uses less resources...