Ive already a seagate 7200.11 500GB fry up on me. I got it RMA'ed and now I have a 7200.12 500GB drive. I have 3 drives on it(135+135+194GB). Drive 1 is about 30% used. Drive 2 is 95% full. Drive 3 is about 145GB used. Also, I use another HDD 160GB Hitachi for OS, which in 3 years has never given me any problem. Drive 1&2 haven't yet given me any problems. Drive 3 is beginning to give me a headache now. There are two video files which won't copy anywhere. I was taking a backup of my HDD on my friend's 1TB and apart from these two all of my HDD was bakd up. One of those was copied 85% and then it froze. After a while, when i went to my computer, all the three drives had disappeared and only my other HDD was displayd. I tried restarting, but I still couldnt see the drives either in ubuntu/kubuntu or XP. I had to shutdown the PC and wait for arond one minute and reboot it to see the drives working again. The same thing happened with the other file. Both files are playable as far as they copied on the external HDD. These are the only two files which give tis problem. Bad sectors? When i tried chking the disk using tuneup, it froze when going through step 4 of 5 checking file data at around 50%. Again the drives disappeared. I have double backed up my HDD, so i can format it. Wat isthe prob and what should I be doing ideally?