Help Needed With Primary Key And Identity

I have some code in my ASP.NET page which uses a SQL 2000 Database that was created before creating the ASP Page. The problem I'm having is using an insert statement such as the following example from the DATAGRID example on the Matrix Product. I want the option to create new rows but my Primary Key doesn't allow Nulls and when I hard code a number in the first field of my table for my ID...it's not automatically generated. I've looked through this forum but I'm having some problems understanding what others have done with Identity or GUID's...etc....:





Sub AddNew_Click(Sender As Object, E As EventArgs)





' add a new row to the end of the data, and set editing mode 'on'





CheckIsEditing("")





If Not isEditing = True Then





' set the flag so we know to do an insert at Update time


AddingNew = True





' add new row to the end of the dataset after binding





' first get the data


Dim myConnection As New SqlConnection(ConnectionString)


Dim myCommand As New SqlDataAdapter(SelectCommand, myConnection)





Dim ds As New DataSet()


myCommand.Fill(ds)





' add a new blank row to the end of the data


Dim rowValues As Object() = {"", "", ""}


ds.Tables(0).Rows.Add(rowValues)





' figure out the EditItemIndex, last record on last page


Dim recordCount As Integer = ds.Tables(0).Rows.Count





If recordCount > 1 Then





recordCount -= 1


DataGrid1.CurrentPageIndex = recordCount DataGrid1.PageSize


DataGrid1.EditItemIndex = recordCount Mod DataGrid1.PageSize





End If





' databind


DataGrid1.DataSource = ds


DataGrid1.DataBind()





End If








End Sub