What Link says is accurate. I would recommend two pieces of software if you are getting a firewall and trojan remover.

The first is ZoneAlarm Free (www.zonealarm.com) which you should never be without. It is a definitely 10 on a scale of 1 to 10.

The second is Trojan Cleaner (use the free 30 day trial at www.moosoft.com) which will help detect and remove a Trojan if you have one. Sometimes, it can alert constantly and is more and more helpful the higher your technical knowledge is.

Cr0n0 is really not the kind of person who would do this, in my opinion, but be safe and download these immediately. If it detects something, find out who the sender's ISP is and report them to abuse@. Make sure to include their account name, specific info, and a chatlog if possible.

Good luck,
Trafton

EDIT: Roseta, while I'm not sure if you trust me enough, private messaging me the firewall log or emailing it to me at traftonofjj2@yahoo.com would be very helpful. Please do not post this here, as I want to protect the security of innocent people that your computer may have connected with for various reasons.