whizpopthat, your method will not work in any way. If it was that easy, why would people ask this question? I mean, if someone wants to open his mail in firefox, they probably have set it as their default browser already. If not, then doing so won't solve the problem.
FFinWLM, If you use XP SP2 you can do the following (might work on Vista too, but I haven't tested):
-Open regedit
-Navigate to
[HKEY_LOCAL_MACHINE\SOFTWARE\Clients\Mail\Hotmail]
-Create a subkey called "DefaultIcon" (if it isn't there yet)
[HKEY_LOCAL_MACHINE\SOFTWARE\Clients\Mail\Hotmail\DefaultIcon]
-Change/set the default value of the DefaultIcon key to
"%ProgramFiles%\Internet Explorer\hmmapi.dll",0
-From the Hotmail key, navigate to shell\open\command
[HKEY_LOCAL_MACHINE\SOFTWARE\Clients\Mail\Hotmail\shell\open\command]
-Set the default value of the command key to
"%ProgramFiles%\path\to\firefox.exe" http://mail.live.com/
Now, I don't use Windows Live Mail, so I don't know if this method has the same functionality as with IE (eg. auto login, that kind of stuff), but it does open Windows Live Mail in Firefox from the start menu.
This probably won't change the way Windows Live Messenger opens the mail, so you might still need stuffplug to do it from there.