Just had another system crash (had a few of the same over the past couple of weeks). Reason according to Event Viewer is a “Bus/Interconnect Error” followed by two “Cache Hierarchy Error”. Temperatures (have been looking into this for a while now, as such had HWinfo set to log to file, were in check at the time of the crash.
Vibration can loosen some connections in your PC. Heat and weight can warp the PCBs. Try to first de-dust your PC, disassemble it (not completely), reinsert your CPU, apply new thermal paste, put the heatsink back on and reinsert your RAM and PCI-E devices, see if that helps. Otherwise, if you still encounter instability issues, the mobo or CPU may be almost toast.