.
As you imagine, this does not sound like a Good Thing.
DO NOT add "new simple volume." In fact, don't do ANYTHING with disk management. Using this utility to look at your hard drive is about the only safe thing you can do ... virtually all other options will repartition/format/ etc. suchlike actions that will irrevocably erase existing data on the drive.
Step Away From the Disk Manager!!
Also, disconnect the drive (both power & data cables). Each time you power it on might be your last, so only power it up when you are actually ready to take actions. If you keep rebooting the computer with the drive connected, each event could be reducing your opportunities.
We need to determine if you have a hardware failure, such as your controller going south, or if it's a corruption of the file allocation tables or somesuch thing. Hardware failure, there's almost nothing you can do. If it's a corruption of Windows file access, there are some options, including the possibility to boot from a linux recovery disk.
Now, take a few breaths and get out of panic mode. This is exactly the desperate frame of mind under which irreversible mistakes are made.
Is there anything on this disk that you need immediate access to? If not, take a breath and get in the frame of mind that this might take a few days. Or weeks.
The Bad News: since Disk Manager shows basically your entire drive is now unallocated space, there is a pretty good chance that the data is already unrecoverable. Accept this possibility and realize that there is life beyond anime.
Meaning:
IF there is a way to recover, you're ahead of the game.
Is there other data on this drive that is critical? This should be the focus for recovery options. Cut your losses for the stuff that can be replaced. Set priorities for what gets recovered first. If the drive is mechanically failing, you may have a VERY limited bit of life IF you can get access again ... so you want to recover that one or 10 GB of critical data first and try for the 590 GB of replaceable data afterward.
I went through this last June when a power outage cooked off a 400 GB and a 320 GB drive, both of which were pretty full. So, you have my sympathies. My story didn't end so well. I got about 5 GB of data off one of them before it went completely dark. I can't even reformat those drives ... they're gone for good.
Other folks here have better knowledge than I do for your situation.
Which version(s) of windows are you using? Do you have access to more than one system?
Which version of Windows was the drive formatted under? Is the drive one that you placed into an external case yourself, formatted, etc.? Or, is it a pre-packaged end-user solution? Which one?
The drive itself: can you identify the exact model?
The Western Digital website may well have diagnostic and recovery utilities for their product: search for them. I have the disk diagnostic, which can read all the SMART info and indicate if the hardware is failing.
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EDIT: I'll try more later, but busy now. Also, I'm not the best person for this; my success rate is dismal over the past several years. ]
