I got this information from mailing list. yesterday I didn't know why my pc always heavy to be loaded. and now i got the answer read Firefox Flaws For A Simple Way. if you use Mozilla Firefox 1.5 as your default browser. type Ctrl+Alt+del or open Task Manager. You will see how much memory being used by firefox.
Notice from jlhaslip:
This should have quote tags around all material which is from another source