I've been having this issue for several weeks now, but it never happened before I upgrading to windows 7. I have 4 physical hard drives, with one partitioned into 3 parts, making 6 drives in my computer. Lately drives have been randomly disappearing from the list. I've noticed that most frequently it's the IDE drives that disappear, but I've had my 1 TB drive go away once and even one of the partitions and my sata bluray drive. I cannot figure out why this is happening. The drives still show up in device manager and disk management, but they appear as uninitialized. I'm scared to initialize them because I don't know if it'll format them, and a quick restart always fixes the problem, it's just very annoying because it always seems that it's the disk that I need that disappears. I'm sure the drives aren't going bad because it's happened to all of them and the bluray drive, my only thought is that it might be my power supply, but it always worked on xp and vista. I have a 500W PSU, and it's always been enough, though I have been looking at upgrading sometime soon. Does anyone have any ideas as to why this might be happening? It's very frustrating having to restart so often.