Chassis intrusion detected

I have windows XP PRO Meadia Center Edition installed in my system and i have added a hard drive today but i am getting an message saying "Chassis intrusion detected" with below lines.

This typically does NOT indicate a hardware failure.
1. Contact your Help Desk if you did not personally open your chassis.
2. Enter System Setup & Set Chassis Intrusion to 'Clear'

I have tried entering clearing Chassis Intrusion but its asking me for a password to do that. I have tried entering the admin password but its not accepting it. What should i do???

As far as i am aware "Chassis intrusion detected" message is related to BIOS and not operating system. So the password that you might be using for logging in to your system will not work. You will have to contact your board manufacturer and ask them.