ASPX form doesn't send any dropdown or listbox data

I am new to .net and would appreciate some advice.
All of the form results are sent, except the DropDownList and ListBox.
code is;
<asp:DropDownList id="Hear_About_Us" Tabindex="85" runat="server">
<asp:listitem Text="Select one" value="Select_one" />
<asp:listitem Text="Direct Mail" value="Direct Mail" />
<asp:listitem Text="Networking" value="Networking" />
<asp:listitem Text="Trade Show" value="Trade Show" />
<asp:listitem Text="Web Search" value="Web Search" />
<asp:listitem Text="Established Client" value="Established Client" />
<asp:listitem Text="Other" Value="Other" />
</asp:DropDownList>

<asp:DropDownList id="product_use_1" runat="server">
<asp:listitem Text="Select one" value="Select_one" />
<asp:ListItem Text="Trade Show" value="Trade_Show" />
<asp:ListItem Text="Special Event" Value="Special_Event" />
<asp:ListItem Text="College/School" Value="College/School" />
<asp:ListItem Text="General Use" Value="General_Use" />
<asp:ListItem Text="Other" Value="Other" />
</asp:DropDownList>

I guess I am missing something but Expressions doesn't help much.

So, where's the part that sends the values? This doesn't tell us anything. Show us the part that handles the sending and we can give it a try.

Steven