3TB MyBook Essential no longer shows up in Windows Explorer, light flashes rapidly

Using Windows 7. I have used my MyBook Essential 3TB for over a year now. I had attempted to create a system backup in Windows 7 on the MyBook and now it is no longer recognized in Windows Explorer.   The HD does appear in Computer Management/Disk Management but shows up as “not initialized”. When I try to “initialize” the drive the error “The request could not be performed because of an I/O error” pops up. Computer Management will therefore not allow access to repair, delete or format the partition or entire drive.  The drive is plugged directly into the wall and I have tried a new USB cable. The drive can be heard starting and spinning.  The light on the front blinks rapidly for 20-40 minutes, then blinks slowly afterwards.  I have also tried connecting to another Windows 7 computer and an old system running XP, all with the same results.

When the lights are blinking, it shows there are activity in the HDD and slowing down means it is going into standby due to lack of activity or idle.

But blinking for 20-40 mins eventhough it is not being used is a little odd.

Have you try another power cable for the HDD?

Make sure it is the same voltage as the original though.