Follow-up:
If you suspect a trojan virus be careful as to what site you visit for help. Many sites that offer help are links to virus, etc themselves. Use only a reputable (well-known site) for info and help. (If your antivirus program doesn't kick it off your computer).
Definition of Trojan Virus
Trojan - A program that has been designed to appear innocent but has been intentionally designed to cause some malicious activity or to provide a backdoor to your system.