Replacing web.config (3.5) with (2.0) for certain web apps

Scenario 

You watch the new videos on ASP.NET and when you download the source code you find out that they are using VS2008 and Framework 3.5, and you still running VS2005 and Framework 2.0, plus almost most of these video can run on Framework 2.0 (VS2008 not installed on any machine at work) you can still run that web application by following these steps: 

First method:

1.       You can delete all the code in the web.config (3.5) and replace it with the code from web.config (2.0).
2.       Then for each page delete these namespace:

Ø       using System.Xml.Linq;
Ø       using System.Linq; 

Second method:

1.       you can keep the same web.config (3.5) and remove everything using framework 3.5
2.       Then for each page delete these namespace:

Ø       using System.Xml.Linq;
Ø       using System.Linq;