If your hard drive's form factor matches the DVR requirements, it will surely work for you. But, the PC hard disks are not made for those regular operations which a CCTV DVR will put it through. Excessive heat will be the first problem you will see on your hard disk. Also, the hard disk may get damaged once the heat reaches its peak limits. So, it is never a good idea to install your PC hard disk into your CCTV DVR.