As of a day or so ago, I seem to have a tremendous problem with my computer freezing up when I'm surfing the Web. I haven't added any new software or hardware. Pages I used to be able to load (but not others) will all of a sudden give me the beach ball of death which never goes away. I'm wondering if this is because I haven't upgraded to Snow Leopard yet. Could that be the problem? I don't want to upgrade just yet because I'm in the middle of several projects and can't risk any compatibility surprises with my software. It's very odd that this just mysteriously started happening a day or two ago.

Snow Leopard has nothing to do with this. If it's only web surfing that's slowing down and not your editing programs then I would assume that either your internet provider is having problems (which could only affect web surfing) or your browser is in trouble. Try another browser if you have one or use a program like Cocktail to clear out your hidden caches.

Marco,

There's absolutely no connection to which version of OS you're using. Chances are Safari's cache is over-full and is literally choking for free space.

Goto the Safari menu and select "Reset Safari" (see pic) and do just that, refresh Safari entirely, close the app (this completes the refresh process) and then try browsing again.

As WH points out, you should download and run a maintenance/cleaning utility and clean up your entire system on a regular basis. I'm a big fan of Onyx.

Well, the problem is happening on the same pages with both Safari and Firefox. I did go into the settings in Safari and disabled and unchecked enable plugins and that seems to have cured it, but then of course I have to recheck to get certain other sites to function properly. Is this a clue? What's my best fix here.

Actually, this forum category is about issues relative to "editing" on the Mac, not general OS or browser troubleshooting. Try posting this problem on the Apple Discussion pages and see about resolving it there.