If all your disks are showing fail, then you are going to need to force two of them online. IF you are 100% sure that NO disks were failed prior to the power outage, then you can force online any TWO of the disks (assuming this was a 3-disk RAID 5). If you are not 100% sure that no disks were failed prior to the power outage, then forcing online the wrong two drives can corrupt/destroy your data. First thing to do: Boot to CTRL-M and go to Configure, View/Add. If you are prompted to choose between Disk and NVRAM views, see what each lists as the configuration. Do NOT save a configuration until you have seen them both and you receive instructions on how to proceed. You may be able to get live, real-time, and free help by calling Dell's technical support line, which should offer support on older machines. (If in the US/Canada.)
Hi there, My server lost power on weekend and can't boot up case unable to find devices. All bios setting gone includes time and date. Here are what I did but not success. My server has RAID with 3 hard drives. First in bios the integrated devices was on off, so I changed it to SCSI, and computer boots up, but crashed on blue screen. Then I changed from SCSI to RAID and got message can't find device again.  I am sure my hard drives was set to raid so I hit ctrl+m to the configuration utility and find 2 logical drives witch are correct, but all 3 physical drives in raid ch-0 are fail. I just want to know how can I keep my data, please help. 
PowerEdge 2600 bios setting