emails sending..that I never sent?

[Cherish Barker]

I'm watching a youtube video about computer viruses sending to friends.. This man started getting emails returned that he never got in the first place, he tracked it to a virus that attached itself to stored email accounts and sending itself out to the people in your contacts. (they're normally in my sent or spam box)

I used to get them (normally on email accounts that i havent used in a few months), but i'm still not sure. I use the virus protection and clean the PC, everything's good. So is it a virus thats making my emails do this or not?

ALSO: i seemed to have gotten 2 different peoples log in information for some websites (twitter and this random dating site that i have never signed up for) I have a twitter of my own, and i wanted to reset my password but got some random persons log in using my email address...and also this dating site, it logged me into someone else's dating profile..I have no clue who these people are and how they got my emails..(Yahoo & Hotmail). Nothing bad has happened to my computer, emails or anything, I just wanna know WHY i;'m getting random peoples login information?


Help? Thank you