Download vids from any site, Firefox issue

Ok, 2 problems:

1) Lately I noticed Stream Transport is broken. I've used it before for downloading videos off websites that my YouTube downloader can't. Now it doesn't detect any videos whatsoever.
I'm open to a freeware that does the same thing and still works. YouTube is iffy for getting anime and movies simply because of all the copyright issues. Be nice to download the anime I'm interested in watching.

2) Mozilla Firefox is acting up. Still my favorite web browser, but ATM I have to keep it to 7 or fewer tabs, otherwise it will start to freeze for a few seconds. When I had my customary 12+ tabs open, I would get the damned "not responding" message for about 10 seconds repeatedly every minute.

I've already given it admin privileges and uninstalled/reinstalled Firefox, but to no effect.

Thanks!