Copying a p[age in VS.net

I have a page in my web project "Webform.aspx" which has the general layout of all my pages and a blank code behind page
.
What I do is :

1) Copy the page and paste it into Visual Studio.
2) Rename it to......lets say "Webform1.aspx"
3) Change the code behing page so it reads
Public Class WebForm1

Whenever I try to run this new blank page I get the error :

Could not load type '_myProject.WebForm1'.

Can someone tell me how to do this. I am finding Visual Studio great for coding but at simple screen handling and general maintenance It is hopeless.

Thanks in Advance

In the top of the HTML side of your page, you'll have:

Code:

---

<%@ Page language="c#" Codebehind="pagename.aspx.cs" AutoEventWireup="false" Inherits="Namespace.pagename" %>

---

You have to make sure that the namespace & pagename parts match that of your new file's. So, if your original file came from:

Code:

---

<%@ Page language="c#" Codebehind="Webform.aspx.cs" AutoEventWireup="false" Inherits="MyProject.WebForm" %>

---

and you copy it to MyProject/Subfolder

Code:

---

<%@ Page language="c#" Codebehind="WebForm1.aspx.cs" AutoEventWireup="false" Inherits="MyProject.Subfolder.WebForm1" %>

---

If I'm not mistaken :p

[Edit]
And make sure that the namespace in your code behind file matches that of the HTML.

Dude, you are doing way to much work. If you got a page template that other pages will be using, you should be using inheritance. Check out this link, it will help you out greatly.
http://www.codeproject.com/aspnet/page_templates.asp

Plus, if each page inherits from the base page, you can change just the base page, and all others get the changes automatically. It is awesome.