Press Windows + R, type in msconfig, and press Enter. Under the Startup tab see what programs are set to be launched at startup, and jot them down. You can compare that with what programs are actually running, and then use the process of elimination to selectively uncheck each of the remaining programs until restarting does not display that alert. Once you find it you can try reinstalling it or asking here to see why there might be a problem and re-enable all other startup applications.

Hope this helps,
John