You need to make your statement clear if you want us to easily assist you on your issue. Second, please try to format your code to make more readable.
Down to your issue, You mentioned signup button isn't firing but I can't find that button in your markup or I am just blind :)
Also you are using a server controls (e.g ASP.NET TextBox) in your form, but your form doesn't have a runat="server" attribute assigned to it. Your button Login fired because you wired-up an OnClick server event to it. Your other Button is of type submit and doesn't have an event handler. Button with type "submit" will submit the form when you click on it. It doesn't fire an onclick event but it will fire the load event. Take make it more clear here's a quick demo:
ASPX:
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<input type="text" name="txt1" />
<button type="submit">Submit Form!</button>
</div>
</form>
</body>
</html>
CODE BEHIND:
using System;
namespace WebFormDemo
{
public partial class WebForm1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e) {
if (Request.Form["txt1"] != null) {
var stringValue = Request.Form["txt1"];
}
}
}
}
Clicking on the submit button will perform a POST and allowing you to get posted values from an input elements.