I just found the answer to the same question that I have but unfortunately it did'nt solve my problem. I just bought a LaCie external hard disc 500GB and it keep saying that there is only 9.99MB free space left. I have tried several times to format the LaCie, and I have also tried to find it under my computer management, deleting it and trying to reformat again. Nothing helps. Please does someone have another solution??? Thank you

unfortunately clicking sounds on hard drives means that it is already damaged

Inside the LaCie D2 250GB (300770) external harddrive's case, is a 250GB IDE (PATA) harddrive that is 3.5 inches across in width.

A desktop computer sized harddrive. (May be a Western Digital WD25000JB)

The harddrive plugs into a small circuit board, (Bridge board), and the circuit board has a USB port on it.

Using this Western Digital Passport for an example,

http://www.xbitlabs.com/misc/picture/?src=/images/storage/wd-passport-250gb/p3.jpg&1=1

Scroll down to the second photo, and left-click on it. The case of the external harddrive is shown open.
Inside is a 2.5 inch laptop sized harddrive.
An aluminum tape strip covers the small circuit board, attached at the back of the harddrive.

The second photo down on this page, shows you the small interface circuit board, that the harddrive plugs into, with the aluminum tape removed.

http://www.xbitlabs.com/articles/storage/display/wd-passport-250gb_2.html

(Another design has wires coming from the small circuit board, to an interface the harddrive plugs into )

It is this small circuit board that goes bad in a LaCie. QUITE common.

Solution?

Simple.
1) Obtain a 3.5 inch IDE external enclosure
2) Remove the 3.5 IDE harddrive from the LaCie's case.
3) Install the harddrive out of the LaCie into the external 3.5 IDE enclosure.

An example of a 3.5 IDE (PATA) external enclosure,

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1733195&CatId=2779

For additional questions please post in a Comment.
Regards,
joecoolvette

have you dropped it? it could be any number of disc errors, two of the most common errors are caused by viruses and dropping. try putting the hard drive in the freezer for a day or so in a moisture and static resistant bag. just a possibly remedy, if that doesn't work, try removing the casing on the hd and setting it as a secondary drive after you plug it inside a desktop computer.

The flickering light signals that the internal controller board has failed. Unfortunately this is terminal, the external case is dead. If you're really lucky the hard drive inside it still has enough life left in it to allow you , when connected directly to a desktop, to copy all your files from it.
After that just junk it and get a new one.

Hi... Problem with your external hard drive, pc don't recognize it...
it possible you have bad sector in your disk drive, or your usb cable is not responding.... the best way to find out open your box then take off our hard drive and install it into a pc and see if the hard drive work... or you box it self the controller inside our external box maybe damage,

Do you have a CD disc software installer of your external hard drive (F.A. Porshe 160GB).? If you got it, you must reinstall it, so that your Imac can detect it. Otherwise, find it at the internet and download it.
The power failure could have damage some stored data about your External Hard Drive in your Imac. That's why, you have to reinstall it. Send us your e-mail comments for us.

go in to add new hardware in control panel and run external drive ere from there use disc if u have one or go to vendor's support page and download driver's from there

solved: after referring to the userguide, I found that I formated my drive with a OS format, which can not be recognized by VISTA >> formated to FAT32 and now it works... 

I am not really sure where to start here because I am a little confused about your setup here. It seems you made a great choice to keep Windows and your data on separate drives. Your primary hard drive is a really fast SATA Raptor drive, which is great, but I would never use an external hard drive for general everyday data storage. Many will probably disagree with what I have to say, but external hard drives should really be used only for temporary backup. I would never suggest using an external hard drive as your only copy of your data or for regular everyday use. There are several reasons for this:
1. External Hard drives are generally slower than Internal Drives.
2. Many of them come preformatted with Fat32, so you are limited to files no larger then 4gig.
3. They are more likely to fail because they are normally subjected to a greater likelihood of accidental bumping or dropping.
4. Many external drive enclosures are not properly cooled for continuous usage and thus lead to premature failure.
5. You often have no idea what brand of hard drive is actually inside the enclosure.

Don’t get me wrong, external hard drives are wonderful and I use them all the time. I have three LaCie 160 gig drives myself that I use all the time for temporary backup, but I rotate them so that I have 3 consecutive backups and would never use them (not just Lacie but any external drive) as my only backup or as a primary data drive. And yes, I have had to replace a few of them due to failure.

So to address your specific questions:

What went wrong? –
1. Bad Cable - Well it is probably unlikely, but I would first try another USB cable just to make sure the cable is not damaged.
2. Power Supply - Try another power supply if you have or can borrow one.
3. Controller Failed – The Controller inside the Lacie has failed.
4. Drive Failure – The Hard Disk inside the Lacie has failed. Drives typically have an average 5 year lifespan, some last longer and some can fail much sooner. Unfortunately, you rarely have any warning, thus the need for backups.

if it is a USB (or you have low disc space), it does take longer to show up on desktop and patience is required... on my iBook it takes over a minute for my Brick to show up... Whether it is USB or firewire, do try another cord (I had similar problem with my lacie firewire external... I used a different firewire cord and all was fine. If you have tried these already, I hope you find the answer... good luck