The information applies to HP Notebook PCs.
Most HP Notebook PCs have SMART (Self-Monitoring Analysis and Reporting Technology System) capable hard drives. SMART is firmware that resides on the hard drive and continuously monitors drive parameters such as performance and error rates. SMART uses a technology known as predictive failure analysis to tell you when a hard drive failure is imminent.
Common SMART errors are:
Hard disk failure is imminent.
A hard drive in the system reports that it may fail.
Smart failure imminent, back up your data
Error 1720 Imminent Hard Drive Failure
HP Hardware Diagnostic errors that start with HD521
The use of SMART does not prevent all hard drive failures, but it can give you the opportunity to back up your personal files and replace the hard drive before it fails.