An alternative method (although perhaps not as thorough as the above) for looking at historical alerts is to go through the 'Message Center' (http://server_name/Orion/NetPerfMon/OrionMessages.aspx)
If you want, filter by device
Select the required time period to report on
Tick 'Show triggered alerts' and deselect the rest
Click 'Apply'.
Clik here to view.
