The WD Blue Caviar is a SATA drive. The bios setup display on the old machine should show what drives it can see. I had a PC where the onboard SATA failed. I installed a SATA PCI card to replace it.

Does the new machine have a spare SATA socket on the mobo? Is there a spare power socket coming from the PSU? If yes and yes, just plug it in and try it. Ideally you'd check the bios to make sure it'll boot from the other drive rather than this old one, but either way it'll tell you if the old drive works. (Booting the new machine from the old HD almost certainly won't succeed.)