It is also possible for the hard drive to fail non-mechanically. By using a special index and file structure, your computer is able to read and write files stored on the disk. Now if this index becomes corrupted, your data will not be able to access the drive, even if the data is still there. For issues like this, using the proper software can do the trick - but it will be quite challenging for some. Lastly, a hard drive can fail because of a physical connectivity issue. This is quite tricky and insidious because the drive is actually working - it is the connection at fault. This could be a port on the motherboard, the SATA/IDE cable and so forth. Issues like this can greatly mimic a hard failure. This can be easily remedied by replacing the faulty cable or motherboard and you should then be able to access your data. Too often, hard drives fail without any warning signs or flags. One minute your computer is working perfectly, the next you are no longer able to boot to Windows and all your data is gone. The point here is that you need to assume that your hard will fail at any moment and back up all the necessary data. If you do this regularly, you are going to save yourself from a lot of headache and stress, if in case the drive does fail.