I ran a Norton Utilities scan yesterday, and afterwards various websites looked extremely strange in Firefox. Worse, I lost the ability to view embedded videos on such sites as the BBC, YouTube etc. Further testing this morning shows that the problem isn't with ALL video content. There are SOME YouTube videos that I can view perfectly well, for example. And while I cannot view content in the MLB.com media player, some embedded video on the homepage seems to work fine. I have updated my Flash plugin to the latest version and the Adobe website tells me it is working correctly. Any ideas what could be causing the problem? Did Norton Utilities delete some file that I actually needed? I have read some forum answers about other problems that suggest I should disable Norton scans with respect to the Firefox folder, and I will do that - but how do I fix the problem it has caused? I have tried a system restore to no avail. I have Firefox 12 running on a Win7 x64 machine. And by the way, the 'weird-looking websites' problem mentioned above seems to have been fixed by reloading each one in turn.