When a Toshiba hard drive has been locked, you will need to unlock it to install new software. You can lock your hard drive's as a security precaution to prevent its data from being overwritten. Unlock your Toshiba laptop from a DOS prompt; DOS is the text-based backbone to Microsoft Windows. Unlocking a Toshiba hard drive takes about five minutes.
Press the "Start" button, then click "Run."
Type "Cmd" into the command prompt and click "OK."
Type "unlock z:" at the DOS command prompt. Replace "Z" with the drive letter of the Toshiba hard drive. For example, if the Toshiba hard drive is the "C:" drive, type "unlock C:"
Click the "X" in the upper-right corner of the DOS prompt to close it.