The only thing I've seen like that is here: 
http://www.xs4all.nl/~ppk/js/flash.html

its a script to detect flash plug-in but it also says that it can be 
adapted to detect other plug-ins instead.  Check it out.

HTH
Phil
>--------------------------------------------------------------
> Hai,

   This is very urgent. In my project if i mouse over i will play in avi 
file.It is working fine.But if Sound Driver's is not installed,it will 
show 
the error message.

  For me i don't want to show that message.If it is installed i will play 
the 
File.