I've been reading little bits in the past few weeks about some advanced disk diagnostics that you can get if you have SMART turned on for your disk drives. I have two disk arrays on my main XP/Pro systems (it is about a year old): a pair of Western Digital 150GB drives, 10,000 RPM, in a RAID-1 array, for system/programs; and a pair of Western Digital 500GB drives, 7,200, in a RAID-1 array, for data. At this point, I've had no problems with my hard disks. Would SMART help me? If so, how do I turn it on? If you have it on your machine, have you found it useful?