When i add the form tag the output changes

i face a very strange problem (at least for me) ,i got the html layout of 开发者_运维知识库a web page from the designer and it is exactly the same HTML of the photoshop design..when i add the HTML tags to my ASP.Net website and add the <form runat="server"> </form> tag after the body tag..some of the divs in the footer appear differently..

here is a screenshot of how the footer should be

and here is how it appears now

Any ideas??

Most likely there are some CSS rules applied to the <form> element which is messing up the layout. If you can post a url to a sample page then we could tell you which rule/properties are causing this.