Windows wants to format My Book 500gig external HD

Hi everybody. I was just wondering what can I do when I have stuff saved but windows wants to format my drive. I backed up my info unto Ext. HD before erasing my entire internal HD on computer. Now I cannot access my saved data, on ANY computer. All it wants to do is to format it. I can unlock it fine with no problems. Help!

The drive is corrupted

retrieve the data with a recovery software

I have used TestDisk and it worked

you can get other options online