Slow computer, Freezes, BSOD (Blue Screen Of Death)
These are very unspecific signs that can be caused by many different things. regardless of any of the potential causes it is recommended that you immediately make a backup
If you’re finding files failing to open and are corrupted even though they saved without problems or you find suddenly are no longer there, you should get worried. This could again be due to a multitude of issues, it is also a typical sign for the beginnings of a hard drive failure.
Bad sectors are areas of the hard drive that do not maintain data integrity. They are automatically masked by the operating system and thus hard to identify, especially if large amounts of the disk are currently in use. Bad sectors can occur on both traditional magnetic hard drives and modern solid-state drives. There are two types of bad sectors — one resulting from physical damage that can’t be repaired, and one resulting from software errors that can be fixed.
When you hear strange noises coming from your hard drive, it may be too late already. A constant clicking sound (click of death) is caused by the head as it is trying to write data and recovers from errors in doing so. Grinding or screeching noises indicate that parts of the hardware are failing.
There are tools that aim to predict hard drive failure by reading the S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) data that is recorded by the operating system.