I have recently had emails returned to my hotmail address as
being unable to be sent to the recepient as they are dodgy(sorry not the technical description) I have never sent these emails, and dont even know who they are being sent to. Can someone 'hijack' your hotmail adress in this way ?
I once had my Yahoo email address hijacked in this way; and found out about it exactly as you have, when some of the emails were bounced back at me. I was very disturbed at the time, and even thought of cancelling that email name, but in fact the returned emails soon stopped, and the episode has never recurred (touch wood!).
I had a similar problem like this 2 or 3 months ago.I would log into my BT email and there would sometimes up to 3 or 4 emails saying that an email i had sent was a failed delivery.I had never sent these emails to these people but for some reason it seemed to think that i did.At 1 point it seemed to be everyday i was getting a failed delivery email sent back to me.As soon as i saw the msgs i would delete them,no point in opening them if i didn't send them.Now that bt have joined up with Yahoo i have had no problems regarding failed emails.
The emails you are getting are unfortunately yet another form of Spam Mail, and happens quite frequently. as long as you delete them without opening them they will stop, as the true senders will beleive your account is inactive. A pain, I know, but they will stop eventually!
Most likely somebody you know has a virus infected PC. The virus will pick up email addresses from the infected PC's address book (including yours) and use them to spoof the 'from' address of the virus infected emails it is sending. This makes it difficult to identify the source of the infected PC. You of course get the reply (normally automated) when the virus is detected by a mail server despite the fact you never sent it. The mails will usually stop when the person with the infected PC finally realises he has an infection and cleans his PC.