Windows 98, actually.

Ah yes, good ol' Windows 98 (The best Windows OS in my opinion).
Oh, and I think you've just solved your own problem. I'm guessing that the new Flash Player you've downloaded is only compatible with XP and Vista and that's why the browser crashes every time you want to watch a video. Try reinstalling the previous Flash Player version.

Also, what Flash Player version you have installed now?

PS: Yuna7780 made a thread - Computer Questions, where everyone can post their computer problems. So if you don't mind could you move your thread there.

sorry, I didn't think to put it there. :o

actually, I downloaded version 9. and that didn't work.

Maybe version 9 isn't compatable with Windows 98?

It's supposed to be.

Wel,l version 9 is the last one that works with Windows 98.
Ok then. First what you gotta do is delete all temporary files and cookies, and check again, sometimes it helps. If that won't help, then try installing the previous 8 version (here's a link).

what about jscript script files? can they be deleted?

Yes they can be deleted, but I don't see a reason why you should delete Javascript or any of it's files. Just delete temporary files and cookies and don't temper with other files. I hope your not deleting them manually.

I know of no other way, as my comp is stupid, and doesn't work properly.

Well did you try using the simple method like: open the Internet Explorer, find and click on Tools in the menu bar, then find Internet options and click on it. There you should see the delete cookies and delete files options, just click on those two and you're done. This is all I wanted you to do.
After that, reopen Internet Explorer, go to Youtube and check if you can watch any videos.