Did you try to open your external box with a drive, and connect your drive directly to your computer (slave it) if you'll see it in windows, that means problem with a box
if you still wont see drive in windows, that means problem with a drive.
Also, if you are saying drive isn't making any noise, make sure it’s spinning up
listen to the box when you press power button. And unfortunately if you still face problems then I guess you must contact a data recovery Lab. One I know is SAlvageData Recovery Lab INC, an ISO 9001 company and here is the address of the lab: -76 Progress Drive, Corporate Park, and Stamford, CT 06902. My friend has faced dangerous problems regarding data recovery and we have seen how this lab has given best result and recovered data. You can also. May be this will help.

A much cheaper option to sending it off to a data recovery service (usually costing a couple thousand dollars) is to use CopyCatX. CopyCatX will allow you to make a duplicate of your failing drive as long as you can get it to power up. Unlike other drive duplication programs on the market, CopyCatX is fault tolerant. It can work around bad blocks on damaged drives and even drives that are going into the click of death to make duplicate to a good drive. Try that with other programs and they'll lock up or fail as soon as they come across a bad block. You can download CopyCatX from SubRosaSoft.com's website, here. Should that fail, you might want to look into a data recovery service, but keep in mind that most charge several thousand dollars for the service. Just another reason that a good backup is worth much more then the money spent on the required equipment.

HELLO
A good peace of software that i use is harddrive regenerator which can be bought in most shops on the internet for about 30 or 40 pounds.
Place the hard drive regenerator disc in the cd dvd drive and boot from the disc and it will repair all your bad sectors on your harddrive and you will still have all your data on the hard drive too.
Job done mate

The product you recommended is for Windows only. Remapping bad blocks on a volume with data on it isn't a smart move. In addition, remapping bad blocks isn't always the best thing to do. In most cases those bad blocks come back and get worse. It's best to just replace the drive should you start seeing a decent number of bad blocks appearing.

sorry mate i thought it said at the top they were running xp pro

True, it shouldn't have been posted in the Mac forums. However, I'm actually moving this to the hardware forums as this pertains more to hard drives than actual operating system usage.

yes mate i agree.
Hard drive regenerator is what you are after kevin , it will repair any bad sectors on the hard drive and you will be able to use the hard drive with no problem.
I have used this software on 3 or 4 hard drives myself and it works every time.
If the hard drive has got a lot of bad sectors it removes them completely , but this is only in bad cases.
Give it a go mate.
Also sorry to say but i have found that the majority of problem hard drives are by maxtor , western digital i would say are one of the best hard drives

Also you can right click on my computer click on manage , then go down to the bottom and click on disc management.
See if it is in the list if it is and it say unallocated just right click on it and press format.
Assign it a drive letter and then format it and at the top once it is formatted in the status column it sure say healthy active.
Now on into my computer and the hard drive should be there under the name and drive letter you chose.

"This unit has years and years of information in it and I really need to be able to get to it."
So, that would seem to eliminate formatting.
You need to get this drive out of the case to isolate the problem.
Attach it to your machine via USB adapter or one of the IDE channels, then see if it spins up or is recognized.
All HD manufacturers make diagnostic software which may help if you run into problems.