Virus? Help !! MSN Hotmail Photo attachments that I never sent?

On my hotmail account, a bunch of emails go out to everybody on my contact list, they're a few photos that I never sent. I haven't opened them, cause I'm sure its a virus. It's sending to everybody on my list, even when I'm not online. How can I stop this? Nobody knows my pword so that's not an issue and I haven't clicked on any mysterious links. What's going on? Do I have to make a new hotmail account?