Edit: Mug, these comments aren't directed at you, please make a separate help thread in another topic. Your error is different.
Ok, good to know. If it's only a few months old I'm gonna assume it's a SATA connector, I don't think many companies made 500GB IDE drives. Also happy you knew to mount and unmount properly, and no power outage. So ya, I'm pretty sure it's some sort of drive failure. With external drives, sometimes it's the interface itself (i.e. the controller between the drive and the USB controller that fails. In order to rule this out, and expose the low level data to recover, we are going to put it into the main computer.
These are the steps I propose, please read them over slowly and carefully and prepare everything you need before you start step 1. If you have any questions, ask BEFORE you start.
1. Get the drive out of enclosure. If it's aftermarket (i.e. an enclosure you bought and put a drive in), you can easily remove it. If it isn't, and you bought it as a retail external drive you'll have to find a way to pry it open. They got it in somehow, so it does come apart. Be careful, no hammers or dropping, I recommend a flat head screw driver in the largest seem on it. Once the case is exposed, you need to usually unscrew the interface from the case and remove the drive from the interface.
2. Now you got your drive you want to save. Hook it up to your machine. Regardless of whether it's IDE or SATA you should be able to support it. If your unsure, list your motherboard/OEM Make and model and I'll tell you. IDE is the big fat wide connector, SATA is the cheap tiny one the size of the thumb. You should be able to look inside and see what you have, once opened you'll be able to tell what the drive is too.
3. Once installed properly, you need to download and run a disk rescuing software. I recommend
spinrite personally cuz it's what I use on failing drives, but a lot of people don't like paying the price (google if your curious more). Linux has an alternative though called TestDisk, it comes on great utils like
System Rescue disk. Download and burn the disk please. It comes with gparted btw as well, so you can see if your partition displays correctly one more time with that.
3b - Note: I just thought, you can at this point use GParted if it detects and recognizes the drive and partitions to mount them graphically and then use one of any means to get data off. That would be DVD burner, USB (another drive), Mount a partition on your other drives internal (the two you started) and copy over, some sort of online storage if you have access to.
4. Now that we got our tools, we get started. Put the sys rescue CD in and boot it. Push enter at first screen to initiate boot and wait for it to stop, it auto configures almost everything. Then when it stops, type in wizard and push enter. Then accept the first option on the main screen, and push enter to select it. This will get the GUI loaded.
5. GParted is in the menu at the bottom (looks like a hard drive), I suggest having a look with it at your partitions and seeing how things are now before proceeding. I assume they won't work right.
6. Now we are going to start up test disk, it's a terminal program so unfortunately no GUI or text-graphics. Push the CD in the bottom right, System > Test Disk. That opens a terminal with the program installed.a The first screen explains it needs to create a log file, just push enter and it will.
Quick tips: Up down left right are the keys to move. Enter selects an option. Tab moves you between menus and or buttons at the bottom (proceed, quit, etc...). That's all needed.
Next, you'll be presented with a list of drives/partitions. Scroll down to the one your trying to save (you should be able to tell). Select the partition (I assume it's one big storage NTFS one) then push enter.
Next screen asks how the partition table was made. I assume your on a standard Windows box, the first option that says intel is the one for you. The others are for specialty, like Macs, Xbox, etc...
Now, new screen, this is the meat of the program. Lots of options, the first one anylyse is what we want. Select it. Next, it will list your partitions. Push right arrow to select backup, this will back up current partition table. Next it will do a quick search, it asks if you want to check under vista, say yes even though I don't think you need it.
Next screen is the results. If they display green, they are ok (will also say so in the bottom part of terminal). If not, it should tell you right now that something is bad. Next step, we will do a deeper search, select the partition we're saving and push enter. Then you can do a deeper search, do so (one of the options at bottom). Takes some time, especially on a large drive.
Once this is done, we will be ready to do get this going. After all this, you'll be back at the main colored screen that says bad/good on structure etc, one after quick search. Highlight the partition we are working on, notice at the bottom there are choices, let's go over them.
First notice after the explanation on how to navigate (see screenshot), it describes the different states. A * to the left of partition name indicates primary boot (this would be an OS), P means simply a primary drive, L a logical one, E an extended space and D means deleted. On my example, I have to partitions, the first is a bootable linux partition, the second a standard swap. Your case will be different, but it should detect what the partitions are and select the right labels accordingly.
You can actually modify the partition's characteristics by highlighting the drive in question and pushing left right, please remember what you started at. This is more if you know for instance the partition on your external drive is primary but detected improperly, then you'd change it.
Now, assuming everything's alright, you can actually peak at the files on the drive by highlighting the partition and pushing p, the left right arrows will navigate you up and down directories letting you browse to make sure it's the right one. Once all set, your going to push enter on the partition with the data.
This is last step, since deeper search has been done, only option is to write the partition structure to the table and hope it works. Once done, quit the program and reboot. This should be it, if not I think your in worse trouble.
If that doesn't restore proper access to the files, I'm gonna have to send you to spinrite. You can get a, uh, "free" version by the same means other people get free software. I'm not trying to encourage piracy, but the author I've listened to speak and really does want people to fix their drives. In fact, a lot of his customers that pay freely admit they took the software freely as skeptics, and paid once it fixed their drives and saved their life.
Note: If this process seems a bit too involved or complex, I STRONGLY recommend you call a friend who is a computer geek, he should be able to help. I've written my instructions best of my ability. Also, two heads are better than one. Please reply with any questions BEFORE doing anything (except download and burn the CD, that you can do anyway).
Note 2: There's no guarantee of data recovery. Neither test disk not spinrite offer a perfect solution. I hope one or then the other will do it, but I can't give a guarantee. If neither program can, you'd have to resort to a professional service and that costs a fortune. This is the best I can offer for free/90 bucks (cost of spinrite, if test disk doesn't work).
Note 3: Added step 3b, also wanted to note that this live environment gives you the option to log onto the internet with a browser and come ask for help on these forums. You can paste any terminal output and ask what to do at a given step. Please do so before committing any changes to drive.
Note 4: Just realized how FREAKING LONG this post is, maybe longest ever to a single case? I should get like 10 or 20 beans for that monumental effort of text. Hope it helps dude. Disk recovery isn't easy, if test drive doesn't do it I'll give you quick instructions on how to use spinrite (it's more straight forward, got a bit of a text-gui to it).
starcraft.man out for now...