Check this one, follow the instructions

http://support.mozilla.com/en-US/kb/Changing%20the%20e-mail%20program%20used%20by%20Firefox#w_setting-firefoxs-mail-client

thank you

None of the methods in that link work. There is also no add-ons for Firefox 6 to make Hotmail the default mailto app.

Just wondering if anyone had anything? This is very frustrating.

Those steps only add Hotmail or Windows Live as one of the choices for mailto.
You still need to select that mail provider in Tools > Options > Applications

• Press F10 or tap the Alt key to bring up the "Menu Bar" temporarily if the Menu Bar is hidden.
• Use "Firefox > Options" instead of "Tools > Options" if the menu bar is hidden.

In the mailto there is no Hotmail option and the javascript:window.navigator.registerProtocolHandler('mailto','http://hotmail.msn.com/secure/start?action=compose&to=%s','Hotmail')

Is not working for me. I'm using Firefox 6

This seems to be a victim of the inability to run JavaScript code via the location bar.

Set the pref gecko.handlerService.allowRegisterFromDifferentHost to true

Create a new bookmark (e.g. on the bookmarks toolbar) and run that bookmark.
You should see a confirmation bar to add Hotmail.
Do not forget to reset the pref gecko.handlerService.allowRegisterFromDifferentHost to false

Name: Hotmail
Location:

javascript:navigator.registerProtocolHandler("mailto","http://mail.live.com/default.aspx?rru=compose&to=%s","Hotmail");

I have done all this already and nothing happens when I put javascript:navigator.registerProtocolHandler("mailto","http://mail.live.com/default.aspx?rru=compose&to=%s","Hotmail"); into the address bar and hit enter. I do not see any drop down box, nothing.

You can no longer run JavaScript code via the location bar.

You need the workaround and create a bookmark with the code in the location field.
Then you can run (click) that bookmark once to run the code.
That should work.

Ok so I created a bookmark of this page, went into my bookmarks edited location to say ("mailto","http://mail.live.com/default.aspx?rru=compose&to=%s","Hotmail"); and it will not save it in the bookmarks it keeps coming back to this page.

You need to paste the full text in the location field starting with javascript: and ending with "Hotmail");

javascript:navigator.registerProtocolHandler("mailto","http://mail.live.com/default.aspx?rru=compose&to=%s","Hotmail");

Alternative:
javascript:navigator.registerProtocolHandler('mailto','http://mail.live.com/secure/start?action=compose&to=%s','Live Mail');

That worked, Thanks for the patience with me and all the help. :)

You're welcome

Thanks for the bookmark tip. It works!

You're welcome