How can I delete multiple Flash downloads and programs?

When I ran my search program, I was dismayed to find at least twenty Flash player items. How can I delete them properly? I don't think that just deleting them from my files will work.

I am unable to get any audio for my You Tube videos and am wondering if there is a connection. The only browser that allows me to hear the videos is Google Chrome and I really don't like using it. I much prefer Firefox.

Thanks in advance