I would suspect that the RAID battery (similar to CMOS battery only usually larger) which allows the configuration to be stored has died. I would look for the battery (sometimes they are primary lithium coin cells and sometimes rechargeable NiCd/NiMH) and determine if it needs replaced. Remove the battery and check it with a voltmeter. Anything under 3V for lithium and under 1.15V for NiCd/NiMH (per cell) is probably dead.