Probably a power supply issue. Just make sure the (12V 1.5A look on the label on yours) polarity is correct. You will usually see a little diagram with three cirlces. The first will have either a + or a - symbol with a line to the edge. The third will be like the first but with the other symbol and a line going to the black dot in the centre. If it is not the power adapter then the drive enclosure may be the problem.