Weeeeell, you can use the drive as external hdd and backup the shit you have. It happened to my OS too. But I had a SSD that eventually got bricked so I ended up replacing the hardware :/
The problem you have lies in the startup sequence for Windows. See if you can start in debug and/or Safe Mode (tap F8 repeatedly after your BIOS screen is gone until you are given a menu). Your Windows will start differently (no loading screen but letters instead). If that does not work you'll have to repair your windows using command prompt on your install cd. Let me know when you're this far.