Change your password:

To help protect your Windows Live Hotmail account, you should periodically change your password.

Sign in to the Windows Live Hotmail website with your Windows Live ID (The user name and password that you use to sign in to any Windows Live, MSN, or Office Live sites and services. If you have a Passport Network, Hotmail, or Messenger account, you can use it as your Windows Live ID.) .

In the upper-right corner of the page, click Options.

Under Manage your account, click View and edit your personal information.

Next to Password, click Change.

Type your old password, type your new password twice, and then click Save.

Notes
Never give your password to anyone. No one from Windows Live Hotmail will ever ask you for your password.
You can also help to protect your account by periodically changing your secret question.