RuntAt error on ASP page

I am having getting frustrated with the <form> tag...
not sure if it matters but I have created a web site with a MasterPage....
Adding a Content page is no problem... 
BUT whenever I add an ASP control I am told that it will convert the page from an HTML page to an ASP page... Okay not a bad thing!  Or is it?
When I run the page (pre-view) I get the following error...
A page can have only one server-side Form tag.
I open the page in Code-View and locate the lines...
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server"> <form id="form1" runat="server">
 I then remove the runat="server" from the <form...> line and it runs great.
Why does it insert the line and then object to it?
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