Website flash video play inconsistent.

Hello, I've been experiencing weird website playback for the past few months and I can't find anywhere on how to fix it after unistalling/reinstalling guides.

I use to be able to play video content from NFL.com and all of a sudden ONLY the 15 second ad will play, then the video screen goes blank and will not play. If I refresh the page, it ONLY plays the ad and won't go onto the video I wanted to see, so annoying! This also happened on the Wingstop facebook page where a video is supposed to automatically load and then you view the contest submission videos, except the auto load video would never play and neither would any of the others.

I uninstalled flash and now the NFL.com videos play no problem, but when I go to the Wingstop ones, it says "missing plug-in". When I reinstalled flash for the umpteenth time, same story, no play on either site. I'm at a loss here and any help will be appreciated. I have a PC as well and there has been no problems but I hate using it. I don't mess with settings very much so if there's any way to default them I would since I never had this problem initially.

Thank you for any help.