*Generally hard disk failures causes huge damages to both the home user and more for the office user. Theres nothing can be done after the failure accept for going for data extraction which causes a deep whole in your pocket if data is very much critical and important, but there are steps which taken in time can prevent accidental failure of your Disk.
1. Always *
Always
*Always. backup all your data in time if possible in every week or two. Nowdays cheap methoda are available such as 8GB DVDs, External Drives, Online Backup etc.
*2. For old disks(i.e more than 2 years old) they produce lots of sound, check for the cracking sound on disk activity . If this is present than make sure to backup all the data as soon as possible as this indicates any sudden death of your disk.
A hard disk works fine for almost three years but after that much time they are unpredictable in terms of life, durability, access time. Hard Disks have a motor to spin the disks and all you know spinning motors speed decreases due to time.
Always wait for 30sec after shutdown to restart the machine becoz hard disks needs time to came at rest before they are able to start again.
Always Defragment the disk as this reduces the disk arm movement across the platters thus increasing the life of the disk.
Hope u find these tips useful to increase the life of your disk and extract the best performance out of it.