Hi! I tried to ask this before but I found no solution. I removed old cookies as instructed but it did not solve the problem. My problem is that all of my Videos are defaulting to low res. If manually set HD will play, BUT HD takes FOREVER to load and will often freeze when playing. This never happened when I first installed Firefox either last year. HD played easily and smoothly. I use Adobe Flash player to view YouTube videos. Thanks in advance for any help you can give!