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Satish Patnaik

I think you need to complete the required input for your site, shows empty content for the menus..

web development instructional material

invalid css
invalid xhtml
If you set up to teach, you should be able to do.
Your own site should be correct

Tables are not used for layout: current best practice is css positioning
Fixed sizes are not used, your site develops horizontal scroll bars at less than full screen, or on small screens
Styles should be placed in external stylesheets and only downloaded once, not in the head of every page, currently the site uses external stylesheets head styles and inline styles referencing the same elements, with the same style.

Get rid of all the blank space in the html, the home page is 21KB and has 4000 lines, ran it through html tidy, 292 lines and 11KB

run your site through Browsershots to see what it looks like on other browsers, and fix any compatibility errors.
and opera mini to fix mobile errors.

marquees are tacky

some checking/correction to do