convert your project from framework 1 to framework 2

When i converted my asp.net project to framework 2 , i discovered that the style of my web project got messed, and after hard work of repairing the css, i found coincidentally that vs 2005 created new pages with XHTML standard and vs 2003 with HTML 4.
so i changed the standard in my master page to HTML 4 and magically all of my css problems disappeared .