My Buffalo external hard Drive doesn't show up on my Macbook

[paulbee]

In the morning i did a software update on my macbook for the first time in months.

In the evening I was using my HD-PC1TU2/BB-EU external hard drive yesterday for the first time in a few months.
I was moving some data on to the Macbook.
A box appeared saying that the Hard drive had been unplugged and data could be lost ( the usual) but I was n't near the drive.
After a few minutes I plugged it back in and no Hard drive icon appeared.

I unplugged and searched some forums

Today i tried plugging in again. the blue light comes on after a few seconds then goes off and then a clicking noise starts as the drive starts to spin. usually a blue light is on the width of the unit but this isn't appearing and there is no icon of the drive on the desktop of the macbok.
Does anyone have any ideas what has happened? and whether I can recover the ( nearly) 1Tb of data?

[Deezy]

Same thing has happened with my HD-PCT500U2/B-US.

Before it started this, it would upload the files very slowly. The videos I had on the HD were dragging along and it took a while to upload a simple MS Word document. Suddenly it just stops showing up on my computer.
When I go to device manager on my PC the buffalo drive is there and it says "its working properly", but it doesn't show up anywhere else and it's not working on my PC. The HD clicks, the fan comes on, the blue light blinks for a second and then stays on, but it doesn't show up. HELP!

[smoothsavoy]

Same problem!