RE: Non-Mounting External Hard drive
"It was my backup disc, so nothing lost. Is there any good testing software ( other than Disk Utility )?"
A few thoughts here.
Does the drive even "show up" in Disk Utility? Even if you can't work on it?
Or, absoutely no evidence that the drive has been connected at all?
If you can hear the drive mechanism physically spinning inside the enclosure, it could indicate that the problem is with the _enclosure itself_ and NOT with the drive. That is, you could take the drive out of the LaCie enclosure, put it into another one, and it would be "alive" again.
Another possibility is that the drive _controller card_ has failed, although the drive mechanism itself is OK. Thus, it might be possible to swap out controller cards, and get at the data. But since you mentioned the disk was used for backup and nothing was lost, probably easier to replace the entire drive core.
In that case, you could put a fresh drive into the old enclosure, and be going again.
But it's important to sort out exactly what's wrong first.
- John