HTML Frame- How to set the target on a l

I have a problem with my html page. I have created a frame and the frame is just a header at the top of the page that is always supposed to be there. Then the rest of the page is a switch between the toolbar and right side of the page which make up the bottom of the frame. My question is, how can I create a link in the toolbar that takes over the entire page including the top frame without opening a new window?

Thanks for your help,
Yousuf