how do you disable hard disk password

I have this problem with my laptop i loaned it out to a friend who then place a hardisk password and now i cannot be in a position to access the computer when i power it up alll of asudden what comes on the screen is hdd password message my laptop is toshiba 4070cds and the hard disk is hitachi. I have tried to go to bio all in vain tried to clear bios by removing the battery and memmory all in vain . what do I do plesae do help .