Hello, I've been having this problem for awhile now and I don't know how to fix it. I use Firefox 19 and upgraded to the newest version of Flash. When I go to YouTube, I get an error, when I play 360p videos sometime sor any resolution higher. I know it's not my internet, because I was able to play HD videos and all resolutions just fine before. I tried other broswers, like IE and Chrome. I still get the same problem. I uninstalled both Flash and Firefox but it still gets the same error. I cleared my cookies like many people have said to do, but that didn't work either. I'm hoping you guys can help me fix this. I would really appreciate all the help I can get. Thank you. 
I will also post my laptop specs, you know, OS and video card to see if that helps at all.
Laptop Spes
OS: Windows 7 64 Bit
Video Card: GTX 660M/Intel HD 4000