Maxtor External HD - Light come on but HD does not spin

[glabels]

External Hard drive Maxtor 250gb when switched on you can hear it running but now is making a small clicking sound every few seconds: What can I do to get this to re-start: Have turned power on & off a few times but does not make any difference: Your suggestions would be very helpful. Do I need to take the cover off..???

 

[glabels]

If anyone else has the same problem - found the problem was a faulty AC/DC adapter:
Light was on but not enough power to spin the drive. Bought a new adapter and all is going great: Cheers