remove hotmail account

My brother went to check his hotmail account on my computer. Now every time I open my e mail, his hotmail account comes up first (with all his e mail stuff) and I have to click it off before I can open my regular e mail account from Windows Essentials 2011. I looked in accounts, but his hotmail e mail account is not listed. While not a major issue, it is annoying to me. Is there a way to remove his hotmail account from my computer. For my self, I do not use hotmail and never had an account with them.
ps I tried to find a solution in the tutorials before posting.

Thanks for the reply, the only account I could find is in the attachment.

He did sign out of his account, but his hotmail account panel to sign in still comes up first. Once I click it off, I can access my regular e mail account. He does not know either how to remove the log-on panel.

This is the strange part, when I click on my e mail icon, first his sign/log-on window comes up. (It requires a password to open it) When I just click it off, my e mail box comes up, then when I want to create an new e mail and click on "to" , his e mail contacts come up.

Is there a way to prevent this from happening? To Gornot, if I remove Windows Essentials 2011, will that remove also all my e mails and contacts or will they be back with a re-install?