This has nothing to do with the flash on youtube. I have been experiencing the same problems. I have a June 09' macbook pro, and I suppose you do too. I believe the problem has to do with the Hard Drive clicks and Beeps people have,
https://forums.macrumors.com/threads/727453/, and the beach ball problem other users (including me) have,
https://forums.macrumors.com/threads/739790/. I've tried everything on that second link, and I thought post #26 fixed the beach ball problem, but it didn't as the beach balls returned after about two weeks.
Firstly, I somehow don't have the hard drive beep problem with my 7200rpm drive. But some users who have the beep, also report beach balling. So I think my macbook pro does have beach balls, with no beeps. Also, I have been led to conclude that all of the june macbook pro's, not just the ones with the 7200rpm hard drives, have the freeze problem. My random beach balls vary from 15 seconds, to once over 5min (which made me hold the power button like you) I have tried everything I could find on these damn beach balls. I believe this to be a problem in the firmware of all the June macbooks. Apple did release a firmware update which fixed the SATA speed problem, but maybe that update could be the cause of the beach balls, since they were rushed to fix it by the many complaining people online.
So, what should people like you and me do? Well I think we should sit tight, and wait. Apple knows EVERYTHING about there computers. They're just very quiet. As mentioned here,
http://www.appleinsider.com/article..._to_fix_bothersome_beeps_in_macbook_pros.html, it seems apple is "highly" aware of the beeps (and beach balls). If you watch the last video on that link, you see the computer freeze for a second. I believe this is a variation of what is happening to us. So I'm not worried AT ALL that my very expensive investment is having hiccups, as I know apple is on top of everything, and will defiantly fix this, as soon as they can. Don't worry, just update your machine whenever the next updates are available.
Also, as I have mentioned many times, everything here is just what I believe. It could be wrong, and you don't have to listen, since there could be more to this. But for now, it's the best answer on this issue for me.
