We slapped a different mobo and are trying different ram...
The computer was randomly beeping for a while with a blank screen when we tried to start it up.
Also, inbetween all this, one of the times we have booted it up it loaded windows, but with the "IRQL_IS_NOT_LESS..." error. I honestly cannot remember what config. we had at the time.
BTW, we have cleaned the top of the processor and heatsink and slapped some artic silver in there, I heard overheating could be a cause of this problem too...