Hi, the possible cause of this:
1. Overclocking (if any).
3. Memory problems (check it with some memory test).
4. Unsufficient Power Supply.
5. Instable operationg or demages in some on-motherboard electronic components (check capacitors).
also, do not forget to provide the BSOD (Blue Screen) error data (at least the error code and its parameters)
or its screenshot.