I have the same problem as many, I guess, and I've tried many ideas of other bloggers. But nothing seems to work on my macbook air OS X10.9.5. When I open the file to download the program, the screen opens to install Flash Player it reads "retrieving 0%" for few a seconds before blacking out and then nothing happens. What can I do? I can't watch anything anymore. The only thing is youtube and it's really slow and jams all the time.
If you haven't rebooted yet, that's a great place to start. At minimum, it will eliminate a bunch of potential roadblocks for other steps.
If rebooting doesn't help, there are links to the alternate installers at the bottom of this page. They should get you going.