deleting a record based on name from aceess db

Question

Hi.
I want to delete a particular record based on name from access database in vb.net

db name: stpl
table name: equipments
field: Mandal,   sal,   Date
eg:    Pune,     2000,  23/7/12
       chennai,  1200,  11/5/12

If i want to delete pune from my record, I just want to press delete button, it should pop-up msgbox asking me to enter Mandal name, And when i enter mandal name: pune, then it shud check with the db whether the record exists, if yes then shud delete it otherwise it shud say:"no record exists".

My code is: here I used textbox, actually i want to use pop-up box.
Iam getting error: object ref set not to instance of an object.

Try
            Mycn.Open()
            Dim command As String
            command = "delete from Equipments where Mandal='" & txtMan.Text & "';"
            myDA.DeleteCommand.CommandText = command
            myDA.DeleteCommand.ExecuteNonQuery()
            MessageBox.Show("Record deleted")
        Catch ex As Exception
            MessageBox.Show("no record")
        Finally
            Mycn.Close()
        End Try

I tried this code also:

Try
            Mycn = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" & System.Environment.CurrentDirectory & "\STPL.accdb")
            Dim sql As String
            sql = "Delete from Equipments where Mandal=" & Convert.ToString(txtMan.Text) & ""
            Mycn.Open()
            command = New OleDbCommand(sql, Mycn)
            command.ExecuteNonQuery()
            MessageBox.Show("Record Deleted Successfully", "Deleting Employee Details", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            Mycn.Close()
            command.Dispose()
            ClearTextBox(Me)
            txtMan.Focus()
        Catch ex As OleDbException
            MessageBox.Show("Please enter Name only", "Deleting Employee Details", MessageBoxButtons.OK, MessageBoxIcon.Error)
            txtMan.Focus()
        Catch ex As Exception
            MessageBox.Show("Please enter Name only", "Deleting Employee Details", MessageBoxButtons.OK, MessageBoxIcon.Error)
          
 txtMan.Focus()
        End Try

But no use.........
help me out