Original title: *** Email address is removed for privacy ***?

Hello all,

I have on two occasions recieved emails from *** Email address is removed for privacy ***. It tells me that delivery of several emails has failed and it shows me the contents which are random links. Now I have also had friends telling me that they have received the exact same emails from me. Now would I be right to assume that my Live account has been hacked? I would have taken a guess at maybe a virus or a Trojan but Norton 360 has never found anything of any kind.
If I have been hacked would it be likely that it was just to send spam and not to access my personal emails and to take everything from them? I'm not one who cleans out his inbox or sent items so there is A LOT of personal information and even personal pictures and documents in there which has me very worried.