If your YouTube is stuck with "java script" and "flash player"
messages, and people are telling you change or install stuff,
DON'T TOUCH A THING!
You'll get nowhere tinkering with java scripts, flash players,
firewall settings, anti-virus utilities, active X controls, pop-up
blockers or various browsers. And definitely stay away from
any software that people on this page are trying to sell you.
None of those things will help you, because your computer
and YouTube were working perfectly fine at one point, right?
The first rule of thumb and best option should ALWAYS be:
don't disable, erase, uninstall, switch, download, alter, add,
change or install anything. That'll only make matters worse.
I'm fairly certain that your "java script" and "flash player" are
fine. Nothing has changed in the past two years. If anything,
the newer "flash players" (especially version 10) have been
known to give lots of trouble to many YouTubers.
Your problem may correct itself within a few hours or by the
next day, because YouTube frequently shuts down many of
its servers every single day without telling anybody (in order
to update stuff). On some of those occasions, it's YouTube's
transmission of "java" or "flash" that's poor, not yours.
If by the next day your YouTube is still "stuck" and showing
you those terrible "java script" and "flash player" messages,
it's very possible that your directories of "temporary internet
files" and memory (often times called "cache") are full to the
maximum and just can't take anymore, the end result being
that YouTube videos never even make it onto your screen.
"Temporary internet files" are tiny bits of webpages that get
permanently put on your hard-drive. They'll stay there forever
and ever, slowly plugging up your computer (much like hair
will slowly clog up a sink drain) until you get rid of them, or
"clear your cache".
If you're not sure how to clear your "cache", or if you would
like extra tips on making YouTube run even better (without
having to buy or install anything), click my avatar and send
send me a message -- ideally with your YouTube or regular
email address. I will guide you step-by-step through "cache"
clearing plus my tips in plain English with full explanations.
Note 1: if you got Google Web Accelerator, dump it, burn it,
trash it, disable it, uninstall it -- do everything you can to get
as far away from it as possible (even though this contradicts
my advice). Simply clicking "Don't Accelerate this Website"
will not help you whatsoever.
Note 2: longer videos require both "Flash" and "Shockwave"
in order to play smooth. You don't require anything more, so
please avoid any and all sales pitches from those Yahooers
who are really disguised salespeople and peddlers pimping
for your dollars. Their "solutions" have absolutely nothing to
do with your question, and their wares may actually worsen
your problem. Besides, what kind of stupid and self-serving
answer is:..[my paraphrase] "Although you can't even watch
or access videos, get this downloader."
Note 3: an unusual fix that once worked for me was altering
the URL "www . youtube . com" to simply "youtube . com",
(or you can even try "ca . youtube . com").