Before calling the "Computer Doctor" do CPR first!
Cables
Check all cables - power, Internet, power strip, etc.
Unplug and replug them to make sure they are secure.
Check to see if the power strip was accidentally turned off.
Program
Close all programs and start over - one at a time.
Reboot
Shut off the computer and turn off all connected peripherals (printers,
scanners, etc.)
Count to 10.
Turn the computer on again.
If it still doesn't work - call your Computer Specialist