Is this a ext drive? Yep if it is inaccessible then Windows (software) can't access it, and you can't get the data off it. Only a Data Recovery Specialist (talking hundreds to thousands of dollars) can remove the data in a clean room environment by dismantling and physically connecting the platters to a very expensive specialized machine if your still bent on getting the files back.
ALWAYS have a BACKUP, BACKUP means a 2ND exact copy of the same exact stuff you want to keep, not just some 'place else' to keep the data as the sole and only copy.