My personal laptop is having an issue. It’s an ancient Dell Vostro 1500 running Windows 7 Home Premium x86. After some recent Windows update, the laptop will spontaneously reboot after logon. (If left at the logon screen, it will stay there indefinitely.)
I have traced the issue to the CNG Key Isolator service—if that service is disabled, the laptop will not spontaneously reboot, but it also will not have any network connectivity.
There is no minidump file, and the settings are enabled so that Windows should create one.
If I do an in-place upgrade (basically a Windows repair), the laptop will boot and run normally with all services enabled, but as soon as it hits whatever Windows update (out of the ~180 that are needed), it goes back to spontaneously rebooting. (I have tried the offline WSUS updater and it runs in the same issue.)
If booted in Safe Mode with Networking, the CNG Key Isolator service starts and runs, and the laptop has network connectivity and does not reboot.
From what I understand, the CNG Key Isolator service is calling to some file or service that is having a problem, but I am not having any luck figuring out what. The Event Log is pretty much worthless. This laptop has multiple specialized pieces of software on it that are either hard to come by or difficult to reconfigure, so a format and reinstall is not an option.