- Check the Event Viewer to check for any errors or warning which may indicate what could be the cause of the restarting.
- Check the task manager for any processes or applications taking up a large amount of memory.
- Try uninstalling any applications which could be responsible as a cause of conflict or system failure.
- Run a system scan to check for any viruses or malware which could be responsible.
- Backup your important data, update Windows, and if necessary check to see if your bios requires any upgrades.