Failing Drive

My Book Essential Edition 2.0 500 GB may be failing.  When I start up in the morning, I can hear the drive clattering and the case vibrating till it picks up rpm and smooths out.  Then it’s OK for the rest of the day.  I’ve run the lifegard disgnostic and it says the drive  is OK.  It’s my external backup for the computer, and I don’t want to wait for a catastrophic failure. The drive is under extended warranty.  Can I get a replacment here before it fails?

Yes, you can RMA it.  I would add that if you are calling it your external “backup” and that drive is the only place you have your data, then it’s not a backup.  To do a backup, you must by definition of the word “backup,” have your data copied in multiple places.  I would get your data backed up to an additional location, before you lose it.