Why did My Book stop communicating with my computer?

Why did My Book stop communicating with my computer?

The device lights up and I hear the disk spinning inside, however it is no longer detectable by the computer.  The indicator light goes from blue to red.  No longer going green.  This device has no physical damages.  It has been working perfectly for 7 years.  I need to recover my data if it cannot be fixed.  A million thanks for your help.