This can be caused by a configuration setting that may have been set by accident, or by malicious software. As a troubleshooting step, go to the System Configuration Utility (msconfig) and check that Safeboot is not selected (checked). You can find this on the Boot tab, under Boot Options - ensure the box is not checked for Safeboot.
To access the System Configuration Utility:
If you discover that Safeboot is checked, then simply uncheck it, click OK and then restart the system.
Example of a correctly configured system:
Applies to: