I've done a search and found plenty of posts where a harddrive is no longer shown under My Computer. My problem is that it is all of my hard drives won't show in My Computer. So this tells me it's probably not all of the power/sata cables all at once. When I restart my PC they reappear sometimes for a while and sometimes for a few minutes and then they don't show up anymore. I went to disc management and they all show up. I am running Windows 7 64bit. The PC is not a new setup and has been running for a couple years. I added a couple hard drives a few months ago but nothing else new. I have a couple network Buffalo HD's that store images of my local drives through Norton Ghost.