Interop not writing in excel file and not releasing COM

Greetings fellow users and moderators.

I am using interop to write to excel but it seems that my project isn't writing that well into the excel file. I want to change a cell with "N" to "D" but the coding isn't right.

Code:

---

                ElseIf check = "N" Then
                    xlWorkSheet.Cells(Int(Listnum.Items(numrent2)), 6) = "D"
                End If

---

The listbox contains the row number in a string and changes it to integer.

Afterwards, I am not releasing my COM the right way... I've been informed that my release object is wrong.

Code:

---

        Try
            System.Runtime.InteropServices.Marshal.ReleaseComObject(obj)
            obj = Nothing
        Catch ex As Exception
            obj = Nothing
        Finally
            GC.Collect()
        End Try

---

Found the answer! it was the order of object releasing!