Firefox password word function

Just been away for a few days but when i got back firefox had for some reason, forgotten my login for Hexus and also hotmail. Now I check both were in the password thing in hotmail. So sorted Hexus out ok, but the issue is hotmail. I went to sign in msn loaded and clicked on the email icon, it opened a new tab but had to enter password etc again. Next time I went to check emails had to do the same as they have not been remembered, and neither did that firefox box asking if i wanted them remembered come up. So on the hotmail sign in screen i clicked for it to always have me signed in. Now the thing is even when I don't have the windows live/msn program singed in, I can still access my hotmail by going direct to the hotmail site from google.

Changed my default back to IE thinking it was firefox, but same thing. Now if I use the home pc and sign in to one of parents msn accounts, I can only get hotmail when signed into the windows live/msn program.

Any idea why it is like this now?

If I switch to IE being the default browser and load up msn, then click on my emails it has not problems at all. Once I have signed out of msn I can google hotmail, and it will want me to sing in. But with firefox I have tick the 'keep me singed in' box, in order to see my emails after i ahve logged into msn. Not sure why this has just happened, and its annoying as even after logging out of msn I can still go to the hotmail page and see it.