Can't download flash player

Hi,

Couple days ago I tried to download flash player. I downloaded installation programs, clicked on install Adobe Flash player and installation started, but then its freezes on 5% and it's not doing anything already for 2 days. I am trying to close it, but it says it's in use. I can't even restart computer.

I have new MAC, I am newbe with MAC, I know that with Windows you can press control alt delete and force stop everything, but I don't know what to do with MAC

Thank you in advance and have a wonderful day