"YOU DO NOT HAVE ROOT PASSWORD". and you are heartbroken . :(
:) well the simple solution to solve this and view youtube videos and flash files without the ROOT password or root permissions is to
1. browse to your home folder
2. Enable hidden folders (on top you have a label VIEW . from that click view hidden folders.)
3. Goto .mozilla and create a folder named plugins
4. download the flash player from the website in tar.gz format and extract it ,you will get a file named libflashplayer.so
5. paste the file libflashplayer.so in the newly created folder plugins (the path is in your home folder ~/.mozilla/plugins. )
6. restart firefox and ENJOY flash and youtube !!!!
It works because Mozilla Firefox also uses ~/.mozilla/plugins for flash player.