You can select the Normal startup, Diagnostic startup, or Selective startup option in the System Configuration Utility tool (Msconfig.exe). If you select the Normal startup option, the option may change to the Selective startup option when you restart your computer.
The Normal startup option reverts to Selective startup if you select any of the options in the Advanced Troubleshooting Settings dialog box in Msconfig.
To use the Normal startup option, clear all of the check boxes in the Advanced Troubleshooting Settings dialog box.
This behavior is by design.