Symptoms of hardware failure or system file corruption may include:

Your computer won’t boot

You receive error messages such as "Hard disk drive failure", "Hard drive disk not found", "Boot disk not found"

A secondary drive won’t show up or allow you to see files

Here’s what to do:

Backup data if possible.

If you’ve recently installed software or made system changes, perform a system rollback (if Windows will boot).

Perform Check Disk (Chkdsk) from the recovery console.

Check the BIOS to be sure it detects the drive.

Check all connections and verify no pins are loose or bent. If possible, replace the power source and cable to verify that’s not the problem.

Run diagnostics as included with your system. If none are provided, check your hard drive manufacturer’s website.

A USB adapter kit will allow you to plug in the drive via USB, or you can install it on another system as a slave. Try to perform any of the above steps.

If it’s your C drive, reinstall Windows.

If it’ still out of service, you have to make a decision:

If your data is not that important, you can reformat. At this point, you should be sure to keep a backup of all files as this drive may be dying.

If your data is valuable, you can pursue data recovery. There is software available on the internet, or if the problem is severe, you can consult an expert; they can provide an estimate in advance so you can decide whether to spend the money.