I bought a brand new HDD - WD20EURS as my old HDD was creating problems. I Installed Windows 7 and copied all my files from my old seagate HDD to this. Everything was fine for the first day, but today whenI restarted my system, WD HDD was not detected in BIOS. I tried unplugging the cables but did not help. Then I swapped the cable with my DVD drive, it worked but when I restarted again, it was gone. I unplugged, swapped etc. atlast it started working. Now it seems to be working, but not sure it happened. Can you please let me know what could be the reason for this? If you think it is HDD issue, the I may have to replace it at the earliest. Awaiting your reply.