What's wrong with Adobe Flash?

Up until bedtime last night, I was able to watch things such as iPlayer and YouTube videos. Today, every time I try to do this I get a message saying that I need to install Flash - I already have it installed, for Pete's sake! I have tried uninstalling my old version and installing Flash again - a procedure that Adobe reckon should take a minute, whereas I've been sat here for twenty minutes already and Flash is only 25% downloaded. I have not installed any new programs or software lately, so I have no idea what is causing Flash not to work; I have shut down everything except this page, as per Adobe's instructions, and installation is still crawling at a snail's pace. I'd just like to finish with a quick moan; I think it's unfair that Flash is the only thing we can download to enable us to watch video content. It doesn't work - I couldn't tell you how many times I have had to restart my computer because Flash has malfunctioned - and I am getting no helpful pointers from the Adobe website.