I had a laptop - the screen of the LAptop got damaged. It had a internal 500gb WD SATA HDD. Since there was lot of Data on it I bought a external casing for this and tried using same - however it is not detecting. I am using Windows XP - Prof
Is it detected in the system BIOS? If not then likely a drive problem. Double check your connections. If it is in the BIOS correctly, then in XP go to control panel, admin tools, computer manager, drive management. See if it's listed in there and maybe doesn't have an assigned drive letter.