I put this together over the past few days, after resuscitating an old custom inventory we had in our NS 6.0 environment. It queries the Event Log for particular error messages that frequently indicate a failing disk (with a source of "Ntfs" or "Disk"), and additionally leverages Windows' support of SMART reporting on hard disks via the WMI class MSStorageDriver_FailurePredictStatus, and reports data back to the Altiris CMDB. I'm including both the Custom Inventory data class and the Task export. You should import the DataClass into to Settings > All Settings > Notification Server > Resource & Data Class Settings > Data Classes > Inventory > Custom (it should create the entry in the normal Custom Data Classes tool automatically).
I'll be back later with the corresponding reports.
I've only tested this in NS 7.1, but I see no reason why it wouldn't work in 7.5 and 7.6 as well. We used the run the earlier version of this on Win XP systems, but I have only tested on Windows 7 x64 with this iteration, but again I'm not aware of any reason that it wouldn't work on Win 8.x or Win10.