Infected MSN chat bot?

Hello, fellow Geeks!

I'll keep this story short. About a week ago, a friend signed in on Windows Live messenger. Seconds later "my friend" started talking to me, and after a few messages, I knew right away that it was a bot. The bot comments is what you would typically expect from a bot. Asking me to join AdultFriendfinder (or might be something else) and sending me links and obviously I didn't go on them. Anyway, just tonight a friend said that I sent her an offline message to her! She copied and pasted it and I knew it wasn't me or anyone else. So, I asked about 10 people on my contacts if they have received any strange messages or strange offline messages and they said no.

I've never had one of these bots before, so I scanned my computer with: Avast, Malwarebytes', superantispyware, online Norton and Online Microtrend scanner and I got nothing, just a few tracking cookies.

Any ideas?

Thanks again!

Run a scan #1 and than #2 @ Simple and free guide to removing malware

Good luck!