Sounds like some kind of phyishing virus or scam where "phyishers" masquerade as a website you know, or email you correspond with, then either hack your account for info or ask for info as if its someone you recognise.
A guy i work with unknowingly had on on his pc recently witch was asking for details from his mates in around about kind of way, the only way he found out what was going on was the emails where been sent out from his computer late at night, early morning. He had to close his email address to clear it but had past it onto two mates in the mean time.