A system I built some months ago has suddenly started behaving badly and stopping with BSDs. All mini-dumps are corrupt so no clues there - it has to be a driver but why would it only happen at the client's and never ever happens on my workbench? Tests on the RAM finds nothing, the CPU temp at idle is < 35C. There are no faults on the hard drive. The error message I get is "irql_not_less_or_equal" and a hex number - which is always different. The only thing different is the monitor (I brought the mouse and keyboard from the client's place) - and I have tried the three monitors I have in the wksps and it is fine on all of them, running for hours on end and all apps opening and closing without error. Take it back to the client's and within about 10 minutes the thing has crashed. Anyone got any ideas, please?