Any of you guys know how to get the name of the default web browser on the user's PC?

My app needs to be able to provide enhanced functionality for Firefox if the user has it, otherwise it just operates normally using Internet Explorer.

I imagine its a registry key that I need to check but I'm unable to check at the moment because I am running linux at home (my development machine is at work of course ).

Also does anyone know of a good source of windows-compatible commandlines for both IE and Firefox?

Basically what i need to be able to do is this...

if default browser = firefox then
[launch 4 HTML files in a single firefox window (one tab per file).]
else
[launch 4 separate IE windows, one for each file]
end if.

Also if it is possible to fin out he version number of IE that would let me open multiple tabs in IE7 too.

Cheers

Wosser