My external drive stopped being recognized by Windows explorer.
I use XP Pro and one moment everything fine and next thing I know I can't access anything.
Already re-booted, tried a different USB Port, nothing.
Windows shows the drive is there but no accessibility.
Follow hpfreak's suggestion but also try a different USB cable that you know works as the cable may be bad.
If no luck, and if not under warranty, carefully open the case and remove the drive. First touch bare metal to discharge static electricity. Then connect the drive to another PC directly. If the drive now works, there is something wrong with the enclosure. If still no go, then the drive is dead.
Here is a procedure to possibly revive it:
1. Place the drive into a plastic ZipLock baggie and zip it ensuring to remove as much air as possible in the process.
2. With the baggie completely zipped, place the drive in the freezer (position it so that it does not fall or will have anything placed on it -- keep it safe from damage while in the freezer).
3. Let it freeze over night -- one full day if possible.
4. Remove the drive from the freezer and carefully place in the refrigerator to thaw it out slowly. Leave it in fridge for a day (at least overnight).
5. Take the drive out of the fridge and let it sit in a safe place at normal room temperature for about 30 minutes.
6. Install the drive, reconnecting all cables, etc.
7. Connect it to the computer. In my experience, 8 out of 10 drives will revive and be usable.
8. Immediately copy your data to the back drive asap. Don't wait, do it NOW. About half of the drives I have revived like this died again at some point in the future (weeks or months later) and the others still go on. Do not trust revived drives, so back it up immediately.
9. Once all backed up, reformat the revived drive (this will wipe everything clean and it will be set up for re-use. Don't use it for anything important though as it could fail again). With a little luck, this routine should handle your situation -- it has been VERY successful for me....
The main reason for hard drive failure is overuse of the drive. It is mechanical, and after a certain amount of use it will wear out (that's why freezing it resolves most failures -- it expands and contracts the moving parts enough to free them up so it functions again).
You've probably heard of "fragmentation" and that you should "defragment" your disk drives, but why?
Fragmentation is basically broken-up pieces of files and free space randomly scattered all over your disk. The disk has to work MUCH harder to save files in pieces and then to find all the pieces again.
This slows your computer down, but it also wears out your disk: the more the disk is used, the faster it wears out.
Each piece written is one more disk use than would be used if files were written in one piece.
Each piece found is one more disk usage than would be needed if files were in one piece.
Some files are broken into thousands of pieces, so writing such a file would mean thousands more disk uses than needed and the same goes for accessing the files later on.
Many disks have tens of thousands if not hundreds of thousands of files and the vast majority of these will be fragmented.
Do the math.
Basic defragmenting finds all the pieces of a file and puts them together, saving time.
Windows has a built-in defrag tool, but it is not meant for heavy use. Many users complain it can be very slow and that the PC cannot be used while it is running (some users with large disks complain that it did not completely defrag their disks despite running all night).
It sounds like the drive has died, but before you do the freezer trick (which in my experience does not work) try the hard drive with another USB interface or connect the drive directly to the computer. De-fragmenting a drive or even running Check disk puts a very large strain on a weak hard drive and should only be done once any data has been removed.