First you should never turn off or on a computer with a External USB HDD Fitted. The drive just has the power removed and is not correctly dismounted leaving the drive to fend for itself which [b]Always[/b] eventually results in Partition Table Corruption.
The Address you gave for this drive is broken and currently not showing anything but if you have had the drive for a few years it's most likely a IDE Drive and you can either mount it inside a computer, fit a USB Cable or buy a new External Case.
If you fit it as an Internal drive there may be some issues particularly if your computer only has the 1 IDE Chanel. What happens is that the IDE Primary Chanel is always the Hardware Default C Drive so if you fit it as an internal drive it may prevent the computer booting. However if you have more than 1 IDE Chanel in the computer fitting it to the Secondary IDE Lead and adjusting the jumper to Master, Slave or Cable Select will be all that is required. However if you keep it as an external drive you need to keep the jumper set to Master.
If you want to fit to another Enclosure look here
http://compreviews.about.com/od/cases/l/aaBlknUSB2Enc.htm
There are several types of Enclosures the main differences being there are ones for SATA and IDE Drives and then they are broken down further to Desktop and NoteBook Drives that they can use. Here I would imagine that you have a Desktop IDE Drive which requires a External Power Supply of 12 V DC to power the drive.
If you want to use a USB HDD lead look here
http://www.overclockers.com.au/article.php?id=457812
Now tot he problem of not being able to read the drive. As this has been directly connected to a computer there are several things that could have gone wring here. The most obvious is that it's been connected for long periods of time and the drive has overheated and failed. This happens to most external Drives at some stage though the initial overheating may not appear serious or for that matter even be noticed it will happen and it will adversely affect the drive. To check this fit as a internal drive and test with it's makers testing Utility. As this is a Maxtor you use Sea Tools from Seagate the Maxtor Drive maker here
http://www.seagate.com/ww/v/index.jsp?locale=en-US&name=SeaTools&vgnextoid=720bd20cacdec010VgnVCM100000dd04090aRCRD
You want Sea Tools for DOS and run it from a USB Thumb Drive or CD. Or you can use the Ultimate Boot CD available free here
http://www.ultimatebootcd.com/download.html
Download the ISO File not the Add and burn it to CD then boot off the CD to run the Sea Tools Utility.
If it is just a matter of Partition Table Corruption after you have the drive somehow fitted to a system you can attempt to run [b]CHKDSK /r[/b] on the Disc from the Command Prompt in an attempt to rebuild the Partition Tables though if the Data is [b]IMPORTANT[/b] as apposed to just being [i]Nice[/i] to recover you should stop using the drive [b]Immediately[/b] and send it to your local Data Recovery House.
If you continue to use the drive and unsuccessfully attempt a recovery it's going to increase the cost of a Recovery and make it less likely to recover 100% of the data off the drive.
However if it would just be [i]Nice[/i] and you can afford to not recover any of the Data on the drive you can attempt some of the many available Data Recovery Tools available.
Here is a short list of the better ones
http://tinyurl.com/273ay5
http://tinyurl.com/rmvrv
http://tinyurl.com/yvrsl
http://tinyurl.com/yyk8cm
http://tinyurl.com/382vm
http://tinyurl.com/ynwnel
http://tinyurl.com/nc4kx
http://tinyurl.com/2wox7l
http://tinyurl.com/374d8b
http://tinyurl.com/djw6u
http://tinyurl.com/f73se
http://tinyurl.com/8bd3f
http://tinyurl.com/afu2j
While the last 2 are from the same company they are very different products. Win Hex should only be considered foe use by someone who knows Hex Inside Out while Davory is a great cheap General Purpose Application.
Personally I prefer the On Track Option but it's anything but cheap. However because I use this type of software a lot it's paid for itself many times over by now, for a cheaper option Spin Rite from Gibson Research or Stella have both very good reputations by other TR members.
If you need to use an External Drive for long periods of time you need one with an Actively Cooled Case so ideally you should buy a Actively Cooled Case like the MX1 from Antec
http://www.antec.com/Believe_it/product.php?id=NDc=
And fit a suitable drive of your choice to it.
However you [b]MUST[/b] always use the Safely Remove Option on the Windows Task Bar need the Clock not just turn off the computer. If you do not do this eventually the Partition Tables will be corrupted and in the worst case scenario the Heads will make contact with the platters when the power is removed and the heads have not been parked.
Col