External hard drive mounts but can't be erased or restored

Hi, I've recently upgraded my 20" iMac running Snow Leopard to a 21.5" running High Sierra. My Lacie Quadra HD was formatted on the old iMac and working fine. I've erased all data and installed Snow Leopard from a disk but did it using my old Mac in the hope that I could use it on my new one. But wired up to my new iMac as before using Disk Utility it will not allow the drive to be erased nor restored, nor will it show up when doing an Option restart. Does that mean it's reached the end of it's live or is there still something I can do. Thanks very much for any ideas.