There are so many reasons why your hard disk may crashed:

(1) It may be caused by mechanical or physical problem such as the spindle motor system failure. This failure is usually caused by over-heating. The activity light flashing that you see on your CPU (central processing unit) indicates that its head moves to different tracks. If this movement fails, it can no longer read or write data. Remember, a hard disk is a hardware component, not a software. It is a magnetic device use to store data, it reads and writes data as it spins.

(2) Failure of logical system (the logical partitioned drives assigned as C, D, E, F, G) may be caused by and not limited to corrupt system files, corrupt firmware, registry components and virus infection. Spywares, adwares & all other malicious files may also cause your hard disk to crash.

HINTS:

(1) If you see the activity light flashing but the computer does not boot, the case may be, your files is still intact on the hard drive but becomes inaccessible -- this may be because of logical system failure. Try booting through a floppy disk or use the start-up disk that came with the system.

(2) If you dont see any activity light flashing on the CPU and that the system can not start up (ofcourse after checking all power cables are on) then it is likely of mechanical problem. And notice that if the system BIOS (Basic Input/Output System) can no longer recognize the hard drive, then it is the physical/mechanical system that failed.

The good news is, usually, in todays technology on hard disks, if this problem occurs it normally will alarm you and warn you before it will totally fails, so you could get that chance to immediately back up your files. And there are also many data recovery tools available in the market today. But at times, it is cheaper to replace the hard drive than to fix it (unfortunately).

TIPS & TRICKS TO AVOID THIS DISASTER TO HAPPEN:

1. Keep your hard drive healthy by performing defragmentation at least once a week (others prefers once every two weeks)

2. Run your anti-virus program everyday! Run spyware/adware removal tool at least once every week (there are many available free to download). Keep updates with all these tools and programs too! Turn on your firewall & pop-up blocker, it protects you from intruders!

3. Remove all unknown emails, clear your bulk and spam emails immediately.

4. Delete all internet temporary files (including all offline files)

5. Install all necessary updates on your computer

6. Be very careful in downloading files from different sites (firmware usually fails because of this)

7. The last but not the list take backing-up your hard drive on a removable disk or tape as a serious task for you to do at least everyday or once a week especially if you are using it for business purposes!