I have a HISHARP DVR HS-DM8030 and i intend to back-up it's entire content of 250GB. So I purchased a 500GB external SATA hard drive (USB) but oddly the dvr does not recognize it. It however recognizes my 1GB flash drive. I really need to copy the content of my DVR. I also tried taking out the Hard disk from the DVR and connected it to my PC. But Windows does not detect the drive. what device or software I need to do that?