This can clear troubles like slow computer operation, odd colors on the monitor, missing functions or results from functions. If you are about to run a mission critical task it is always a good idea to start fresh with a new restart from zero. Apple equipment seems to require less rebooting than Windows computers but they are not immune to problems and can require restarting as well.

Unplug the power cord from the rear of the CPU or from the power strip. This allows the electric to drain completely from the internal components to allow for a clean boot (Restart).

Unplugging the monitor at the wall or power strip will reset the internal electronics and clear any errors that can be held internally.

Keep an eye on the screen for any notices. If you see a notice please write it down or take a picture of it with your phone.

You can try several apps and compare the operation and speed to what you remember. If it seems ok, you are finished. A second test can be to run speedtest.net to see your internet speed. It should be around  90 to 115 for a download and 10 for a upload.

BE SURE YOU UNDERSTAND WHAT CHANGES WILL DO TO THE COMPUTER BEFORE ENTERING THE BIOS.
When the computer is OFF
For Greg and Heathers desktops, tap F2 while turning on the power.
For other Dells try Pressing delete key while pressing the power button
As soon as you see the window in the lower right hand corner of the screen press F2

You are now in the BIOS setup, do not make any changes until you fully understand the outcome will be. Navigation instructions are listed on the bottom of the screen for the keyboard navigation.

The Deep Sleep Control is default enabled in S4 and S5. This prevents a bluetooth keyboard from waking up the computer from sleep.