II've just been out for an hours walk with the dogs. IN that time my Yahoo email has been "hacked" and i've sent 496 emails.
Some people have responded and warned me of this.

What do i do now?

I've deleted everything related to them, running AVG now. I also have spybot to run.

Report it to Yahoo for one, if you can login then change your password. Incidentally, they could just be using your email address as the From field. It doesn't have to have been sent from your account. I could send an email as you if I wanted to.

mmmm - i got aload of failure messages back to my account, and people notified me as i said that i'd emailed them. In the subject file were peoples names , obviously to encourage them to open the message.
It could have been as you say.
I've deleted all the contacts and now i'll change the password.

Have a look in your sent folder, are the reported emails in there? (assuming yahoo mail has such a concept as sent folder!).

If the emails are not in there then it may well be just some automated script setting your address as the 'from' field. In which case, not a lot you can do :(

yep i got a list of sent messages - funnily enough i'm on my own mailing list and haven't recieved an email.

It might not be a virus - as its a webmail service all that needs to happen is for someone to discover your password.

This could be because you have a keylogging virus or trojan but it could just be because you had a 'weak' password which was easy to guess or could be 'cracked' by trial and error.

Examples would be words or names, using all letters and no numbers, or using something silly like '54321' or 'password'.

I was just going to post with a similar problem when it brought this thread up, I have found that emails have been sent to people on my contact list during the night apparently from my email address (Hotmail).
I have checked my sent items folder and found it to be empty but I haven't emptied it, I've run Malwarebytes and MS security essentials but nothing found.
I have just changed my password.
Any other suggestions?

If you remember a few years back Hotmail was brought down completely - crackers (as I prefer the analogy to safe crackers - hackers are good at coding and testing system security - not breaking it/into it!) could be attacking the webmail servers without even visiting your machine.

I was just going to post with a similar problem when it brought this thread up, I have found that emails have been sent to people on my contact list during the night apparently from my email address (Hotmail).
I have checked my sent items folder and found it to be empty but I haven't emptied it, I've run Malwarebytes and MS security essentials but nothing found.
I have just changed my password.
Any other suggestions?

This happened to my Hotmail the other week. I think Hotmail knew of a problem, as they locked my account and I had to send them some info to get it unlocked. You may well find Hotmail lock yours as well.