If it doesn't show up in Disk Management, either in this PC or in another one, all you can do yourself is try if it turns up in Linux, either in the File Manager or in the default partition editor GPARTED present in most distros. A Linux disc or stick to boot from can be made for free (for example, Mint or Ubuntu) or download and burn the GPARTED disc.
If it doesn't show there either, it just broke. Can happen with 9 year old disk. Then find a data recovery company like driversavers.com (or many others) to get your important data off it. That's not free at all, but hey, think of the time you saved by not backing up for 9 years
On 10th May, I downloaded a Windows 10 update which rendered my old GPU incompatible. I reinstalled Windows 10 before realizing all I had to do was switch GPUs.
Following this, my old Internal Samsung HD502HJ stopped showing up in "This PC". It doesn't show up in Disk Management or anywhere else other than in the BIOS. It was working perfectly fine and never experienced any issues with that drive for the past 9 years before this update came along.
I tried switching cables around, I tried it in a different PC and tried a few other things with no luck.
I have a lot of important data on that drive and I was foolish enough to not back it up.
Any ideas?

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