(got it from http://helpx.adobe.com/flash-player/kb/archived-flash-player-versions.html you can also try previous versions, fp11 also worked)
2. extract the file flashplayer15_0r0_167_winax.msi
3. right click the file and click „install“
4. check if it worked by visiting this site or youtube: http://helpx.adobe.com/flash-player.html
The „normal“ way of installing Flash Player 15 (either through adobe download page or Windows Store) seems very tricky mostly fails.
it’s understandable that m$ wants flash under it’s control – rolling it by themselves to mobile and desktop.
seems like the “rolling for desktop” is not working yet. this guide only works for desktop.
if you have problems with flash on mobile… call m$. (don’t ask me for the number… i am not the senior gold member)