how can i refresh the content page without refreshing the master page. i dont want to use frames, so came up with master page.i also wanted the master page to be fixed without scrolling and only the content page to be scrolled.

To make one section of the page stay in place while the rest scrolls use position:fixed in the CSS.So, if you have a div or relevant container in the master page use the position:fixed on that.
AJAX will let you update part of a page and should be of use to what you are trying to do.