External drivers doent open

Hello,
i'm using a internal drive that i have connected to a USB bay and using it as an external hard drive and it was working so properly ans suddenly and without getting dropped or fall or anything it stop working.. when i connect the device the icons appears as usual on my computer page but i cant access any partition of the external device and when i check the disk properties it gave me 0 byte capacity... and the file system changed to be RAW ???
i cant access any of my stored data and i cant rename the drive and windows want to format it and sure i cant simply loose all my data stored on it...
please advice what to do in such case
thank you