Last time I heard about this kind of problem, it was because the person was clicking on links to new pages, before the existing page had finished loading. Eventually, Netscape gets confused about what it's supposed to be doing, and locks up. If this sounds like what might be happening, let the current page finish loading before clicking on any links to other pages. If you don't want to wait for the current page to finish loading, click on the "Stop" button on the right of the Netscape menu bar. When the stop button dims, the current page has stopped loading, and you can then click on the link to the next page. The less memory and processing speed your computer has, the more likely these things will happen.
Hope this helps.
Al