Could you clarify in more detail what you want to do:

(1) Completely remove Firefox from your computer (2) Use a different browser as your default browser, but keep Firefox for occasional use (3) Change your Firefox startup page / home page to a different site instead of using the built-in page

turnstone6 said

I want to delete/remove firefox as my browser. How is that done?

Any particular reason why?

Not many other currently supported Release of web browser supports Windows Vista (also WinXP) now days.