Smartdrive both quick drive test and complete drive test failed

Well you can also use the disk utility and run a test from there. If the SMART test fails for example, even though you see that the hard drive is working, it will eventually fail. 

http://wdc.custhelp.com/app/answers/detail/a_id/866/session/L3RpbWUvMTMzOTQyODY2Ny9zaWQvaW5VZmdwLWs%3D