Can't view video on Firefox

I can't view video's on Firefox. I can hear sound, but I can't see anything. Nothing loads up at all. Like on Youtube.com, the video comes up on IE but not on FireFox. Is there any way to fix this? It's been like this for a while but never bothered to ask for help. Thanks.

what version are you using, and have you downloaded the proper plugins? i've only had trouble with quicktime, and nothing else.

>>1

You need the Flash plugin.

https://pfs.mozilla.org/plugins/