First look in the Disk Management tool to see if it is seen there. The appearance in the bios shows that the drive is still in working order while the partition may have lost some information making the drive invisible in MyComputer and Windows Explorer as a logical drive.
Sometimes if seen in either but not accessible you simply right click on the drive's icon and select the uninstall option followed by a full restart to see Windows detect and add new hardware then seeing the drive appear as it should.