Device Lock is specific software. The manual can be found here:
Other support docs are here:
The manual states:
Note: To uninstall DeviceLock, do one of the following:
Use Add or Remove Programs in Control Panel to remove DeviceLock.
- OR -
Click Start, point to All Programs, point to DeviceLock, and then click Remove
If it was deployed via Group Policy or the MMC Snap in you may need to uninstall it the same way.
Edited to add: Simon addressed this in another recent post here. An antivirus or host intrusion protection program may do this and perhaps not DL specifically. You should check the settings on your other security products and see if there are any options selected that deal with the MBR.
Check all your software maybe your drive been protected by some other tools or software