On Firefox, I have the constant issue of a pop-up notice when my computer freezes saying "the Shockwave Flash Plug-in has stopped working" (or is not responsive, or something like that). First of all, what is a plug-in? Second, even when I install the newest flash, I still have the problem. What is going on??? (It happens when I open YouTube videos, facebook, and various other websites. When I get the pop-up, I click "continue running" and after a few more seconds, everything goes on normally.) But what can I do so I don't have that problem? It only happens on my laptop when I use Firefox. I never have this issue on my desktop computer.