Next time you boot into Safe mode:
- Go into the System control Panel.
- Go to the Advanced tab.
- Click on Settings in the Startup and Recovery section.
- In the System Failure section, uncheck the Automatically Restart option.
Next time the system crashes, you should get a blue screen, affectionately known as a Blue Screen of Death.
There is information on that BSoD that will indicate what is causing the fatal crash.