To perform a power cycle, power down the unit and disconnect the power cord. Press the front panel power button 4-5 times to drain residual power. Once this is complete, plug the unit back in and power on. 

This is known to resolve several issues and is the first suggestion for any troubleshooting. This may need to be performed a few times so it would be best to perform this 2-3 times at least before moving to the next step of troubleshooting if you are experiencing an issue.