I have a 250GB solid state drive as the main drive with Windows 10, games, etc. But I just put in a 1TB Western DigitaLhard drive. The Hard drive does not show up in File Explorer, although my SSD and DVD drives are both there. If I go into the device manage, the hard drive is listed, but I don’t have the option to format it or do anything to get Windows to recognize it.
Help! I’m guessing I missed a step or something setting up Windows 10, but I’m not sure what to do now.
Does it show up in Disk Management? If so, does it have a drive letter assigned? If the answers are “yes” and “no”, right click on the drive and give it a drive letter.
How do you get to Disk Management?
If I click on Start Menu, then settings, then devices, then device manager they both show up under the “disk drives” menu in the Device Manager. Right clicking either drives brings up “properties” for that drive, but the only thing I seem to be able to do there is mess with the driver file (reinstall, rollback, etc).
Start, then start typing “computer management”, select it when it shows up, and Disk Management is in the left hand panel
Ok that worked. I formatted the drive and assigned it to E: and it’s showing up on my computer now.
Thank You!
Yay! 
Adding a useful tidbit: the Windows Key + X opens up a list of Administrative shortcuts which lists, amongst others, the Disk Manager too.
You can get the same list by right-clicking on the Start button, which is how I do it usually.
I had a HDD that wouldn’t show up in Windows 10 until I did a Memory Test scan for some reason. After that, it popped up like normal. Weird one, but widely reported fix for HDD issues in Win 10. Something to try for whoever googles this thread down the road.