support.dell.com Basic Troubleshooting 3-3
•Second battery or any other optional device installed in the media bay
•Cables that connect external devices through the input/output (I/O) connectors
and ports on the computer.
Environmental Factors
A number of external factors, including temperature extremes and humidity, magnetic
influences, sources of electromagnetic interference (EMI), and poor input power or
signal quality, can interfere with the performance of your computer and attached
devices. Monitors are especially susceptible to these environmental factors. The
following items can adversely affect the performance of a computer:
•Inadequate ventilation from operating the computer in a confined space, such as
a desk enclosure
•Direct sunlight causing the computer to overheat
•Line noise or power drops and surges from electrical outlets due to poor wiring
•Line noises or surges through telephone lines
•High-voltage electrical appliances on the same circuit or operating in close
proximity to the computer
•Speakers, especially subwoofer, or telephone too close to the monitor,
generating magnetic fields that distort the display image
•Fluorescent lights causing display flickering or distortion
•Electrical extension cords and keyboard and mouse extension cables
•Too many devices on a power strip or multiple power strips from one electrical
outlet
•Electrical conduits in an adjoining wall or elevators on the other side of the wall
•Large metal beams inside the wall behind the computer
If removing potential sources of problems does not help, try moving the computer.
Power
If you are experiencing problems with power to your computer, perform the following
tasks:
•Check the computer’s power indicator. When lit, the power indicator verifies that
the power supply is operating.
•If your computer is connected to a power strip, turn the power strip off and then
on again.
•Plug the computer directly into an electrical outlet, bypassing any power
protection devices.
•Plug a device, such as a lamp that you know works, into the electrical outlet to
make sure the power source is okay.