A recent update replaced the NVidia driver 341.74 ( with 341.92. After the update, the NVidia Control Panel triggered a "stopped working" error, and the program needed to be closed. I removed all the NVidia drivers and software, rebooted, and the new driver reloaded with the same outcome.

When I rolled the driver back to the previous version, the Control Panel worked again.

PC is HP m8530fk, AMD Phenom X4, 2.2 GHz, 5GB RAM, 1 TB hard drive.