OS drive plugged into another computer

[Rumpel]

I found this old hard drive from another computer that I wanted to plug into my main rig. When I plugged it in, the drive wasn't being detected. I looked through partitions, device manager, replugging it in the SATA. Is it not detecting because its another computer's boot drive?

[Damian.Byrne]

Nope. The fact it's another machine's boot drive shouldn't be a factor in whether or not it's being detected. Try going into your BIOS, seeing if maybe the actual SATA ports are enabled or disabled. If you're unfamiliar with that, download the tool CPU-Z, it'll tell you your motherboard model. Then google that model and look for a manual on a support page. 

Or it could just be the drive is dead.