Go to www.hotmail.com and under the bit where you put your username in, click on "forgot password" it will ask you for your secret question and all that stuff...hopefully you will be able to reset your password. That is very important as people hacking etc and getting hold of your hotmail password is fairly common. So change your password asap if you are able to. If then you still can't get into it, there is contact info somewhere on the website.
I had my account hacked into and my password stolen over a year ago, hotmail were NOT helpful in the slightest!