So, I just had to completely clean out my computer. I had to delete all my Flash Player and Shockwave Players. Last night, YouTube told me I couldn't watch a video because I had an old Adobe Flash Player or JavaScript was off. I downloaded Flash Player 10 and YouTube worked. Now, it's doing it again and I can't watch videos but I have the latest Flash Player and JavaScript is on. Can anybody tell me what to do? Thanks.

I just did restart it and the first video I tried played but then the rest wouldn't. Same message. ):
I just did restart it and the first video I tried played but then the rest wouldn't. Same message. ):