What are the best way to launch client exe?
I am creating a web application which need to launch "NXClient" at client machine. So what are the best way to do it ?
This is not possible.
Instead, you can associate an extension with your program on the client, then serve a file with that extension, and the program will open it.
Edited to remove a suggestion that works only in IE, and with annoying prompts at that...
To launch it without user interaction is, as @SLaks says, impossible from pure ASP.NET, and for good reason.
However, you can create an ActiveX control or browser add-on in another language, and have the user install it. However, by definition, that's not an ASP.NET solution, it's an ActiveX solution, or an add-on solution, etc.
Arguably, however, even such browser add-ons are a bad idea, and you need to be very careful not to do it in an insecure way, and should explicitly state what your add-on does.