It seems like an antivirus scan or backup application gets initiated at 12 AM. Please check on it. Also, I would suggest that you run the diagnostics on the computer by following the steps mentioned in the video below and check if there is any issue with the hardware on your system.
Please let me know how this helps.
Sorry for the delayed response. We need to check if the issue is caused due to any application installed on the system. So please clean boot the system using the link below and check if the issue reoccurs at same time specified.http://dell.to/1eOndyH
Please let me know if this helps.