Friends, I have an external USB HD (740 GB). The disc stopped working in Windows. So I decided to recover the data using Knoppix 5.1 Live CD. Knoppix recognized the disk, and I was able to recover most of the data. Because of the lack of time, it took me 6 months to copy the data from the disk. Today I wanted to copy a couple of last folders, alas after copying 60 MBs, the disk stalked. I re-connected the disk, but it has never appeared again. I tried to reboot Knoppix, but without any success. I cannot see the disk. Please advice what should I do. Is it possible to format the disk? Please help. Thank you very much in advance.