Dell Security Manager - Hard disk drive protected by password

My desktop on startup prompt the Dell Security Manager window that requests for password.

It says " Hard drive XXXXX, the system internal HDD is protected by a password authentication system. You cannot access data on this hard disk without the correct password. Please type in the hard drive password.

Desktop Model: Optiplex 7010.

I never set any password before and now i am not able to access the computer. Please advise urgently.

Thanks