Dozens of minidmps this month, hundreds overall. Attempts to load the special BSOD utility on this forum fail with error message, but I have the BlueScreenViewer data. All BC Codes "a" with the exception of one BC Code 50. The advice I find on MS site seems to be try haphazard steps to isolate the problem. Do the minidmps provide no useful information? Is there no deterministic approach to isolate the problem? I have run the preboot memory test with no error messages. PC Doctor finds no problems. The BC Code "a" seems most often to happen when I am away from the computer. Do the addresses and driver names in the minidmp give any clues at all?