The only 100% safe way to proceed is to fit another drive, set up windows on it - then try to access your existing drive. Or acheive the same by putting your drive as a slave into an working system.
Your existing drive may be corrupted beyond repair, or it may be recoverable. If you try to recover it at this stage, you may make it unrecoverable - so - the choice is yours.
There are a number of programs to attempt to recover unreadable drives.
If you put ... recover hard drive ... into a Google search, you can take your pick of many recovery software tools.