Consider a Mac OS X or Linux user that does not have WMP installed. Or a Windows user that manually removed WMP. Or a mobile user running iPhone OS, Blackberry OS, WebOS, Android, etc. that does not have a portable version of WMP available to them.
In short, you can have the content automatically load in the user's default media player for that file type, but you cannot specifically force WMP to open the file. If you're familiar with C#, VB.NET, etc, just set the headers accordingly. If not, you need to learn a .NET language if you want to create an ASP.NET-based webpage.
Oke look this is the problem
My friend made a aspx so when you click on the link it will say download the aspx now instead of automatically opening wmp
So how do i let the aspx opening wmp automatically with out downloading the aspx first