How to test if a hard disk is bad or not

I've got two sata drives in my machine. the one which was only for storage (no os) has suddenly disappeared in windows 7. as I boot, bios finds the drive. I've opened the case and made sure the connections were good. how can I check this disk to verify if it has stopped working and needs to be replaced?

My personal opinion: If a drive has burped all over my data once, I don't trust it again. I sincerely hope that you have backups.

That said, if I understand correctly the drive is detected in BIOS but there is no drive letter. There can be any number of reasons, some benign, some annoying, and some permanent. There are two paths to follow, one to determine if you can see your data and one to determine if you can trust the drive. First thread:

The easiest step is to open Disk Manager and see if the drive is present. If it is, does Disk Manager show it as a partition with data or as raw? The simplest possible solution is if the partition is still there and good, and you just have to assign it a disk letter.

If it's not that trivial, let us know what Disk Manager shows. Then download a first-level recovery utility such as EASEUS Partition Recovery (that's not a plug, it's just the name I remember best. There are a dozen good free ones). Run it against the device and see if it can recover your disk formatting and magically reveal all of the files.

If you don't see anything at this point, I would switch threads, download the drive diagnostics from the drive manufacturer's web site, and run them. If they say that the drive is shot, this is a good place to stop. If not, you can get one of the more aggressive recovery utilities that reads the drive sector by sector and tries to rebuild files. These can take several days for a complete run. They are usually free to scan the drive, but up to $100 to actually recover files if any are found.

Let us know what you find.

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