My DELL XPS 17 L701x laptop was equipped with Samsung Spinpoint MP4 HM640JJ 640GB 7200rpm hard disk. Last month, due to noise and auto shut down, i gave my system to dell service center for repair but took out my hard disk as it was containing "sensitive" data and i don't want to take any risk. Also i needed it for my dissertation. as my all data was on it. In the mean time i bought another Seagate Momentus 500GB 7200rpm drive as the xps has space for one more hard disk. i put the samsung hard disk in usb case which need both side male usb connector. i was having an old connector which i tried to use but i can hear a little sound and it is not detected by my home desktop. so i got a new usb connector and it was easily detected and i used as usual usb external storage. when my laptop was fixed, i took back the samsung drive along with the new one to service center. and when they tried to place both drive, the system didn't responded at all, after some tries, they announced the samsung drive (which was originally shipped with laptop) has gone bad and is unable to detect. so i asked them to only fix newly bought drive in the system and make it workable by installing OS. Now the issue is that my samsung drive can't be detected anywhere. neither in laptop, nor in my home/office desktop. though i was able to use it as external storage before but it suddenly stop working, leaving me nowhere. i have lot of important data on it and i want to recover it myself. other choice is that at least i have do low level format so that i make that data unrecoverable by all means and than i claim a new drive in warranty. as they offered me free replacement coz my system is still under warranty. What i have tried till now? Attached it as internal storage in laptop - no reaction. rather laptop halt in BIOS and no further activity. Attached as external storage - for the first time windows try to detect and install driver for it but fails. later no action if tried to connect with either desktop. i tried on many desktops. Symptoms: while attaching with any system as external storage, the blue led of box turn on for a while but later it turn off as there is nothing attached. and actually there is NO hardware activity as spinning or any sound. the hard drive is totally silent. What i feel is that there may be problem with its circuitry as in the beginning, when i tried to attached it by using old usb cable, it may done some damage in PCB. but i am not sure. Can anyone suggest as what should i do? the major issue is to protect the data inside. It would be helpful if i can recover it as it is very important for me, but in case i can't recover, can i destroy that data? so that i claim warranty? i have less time left for it. please give any advice. thanks for reading.