[help] Firefox Plug Ins

Hello, I was just wondering are there any ways to modifiy firefox plug in set up

manually?

I recently uninstall wmp 10 and go back to 9 and somehow firefox plug in for extensions

such as wmv, wma, asx doesn't work....

So, I was wondering are there any way I can set up the right directory and applications

set up manually on firefox to make sure in order to work the plug in...

tools options filetype doesn't seem to work properly so here I am asking a question...

May be there are some solutions to it I hope...

Thank you in advances...