First, try reading this disk on another computer, just to make sure it works and that the data is still there. You might need to perform backup first before proceeding (if it is readable). If not... try data recovery software and only then proceed.
1) try connecting the disk to a different SATA port on your motherboard and try installing win again.
2) disconnect all other SATA devices and leave only HDD and try again.
3) if 1 and 2 dont help, your disk's partition table probably got corrupted. You can use any linux on bootable USB stick to boot the machine, run gparted and repartition the drive manually. Then you can try reinstalling windows from DVD normally.