Question Is it perfectly safe to put a hard disk drive back into my computer? Is it also fine to put in a brand new SSD in an old motherboard?

[JMusic7]

I took out my WD Blue 1TB hard disk drive a few months back. I tried to connect it to my current PC but it wouldn't show up. Not even in BIOS. I'm about to reconnect it to my old PC. Everything should run properly I'm assuming? Is there anything I should be concerned about when it comes to re-installing it?
I also want to put in an NVME SSD drive. Can I just insert the SSD in the M.2 slot?

 

[USAFRet]

I took out my WD Blue 1TB hard disk drive a few months back. I tried to connect it to my current PC but it wouldn't show up. Not even in BIOS. I'm about to reconnect it to my old PC. Everything should run properly I'm assuming? Is there anything I should be concerned about when it comes to re-installing it?
I also want to put in an NVME SSD drive. Can I just insert the SSD in the M.2 slot?

You'll need to give us a LOT more info here.