Dell Dimension XPS 50 Reference Manual page 25

You can clean a diskette drive using a commercially available cleaning kit. These kits
contain pretreated diskettes to remove contaminants that accumulate during normal
operation.
If the kit does not contain instructions, insert a pretreated diskette into the drive and
turn on the system. After 20 or 30 seconds, remove the diskette from the drive.
A number of devices are available that protect against power problems, such as
power surges, transients, and power failures.
Surge protectors prevent voltage spikes, which occur during electrical storms or fol-
lowing power interruptions, from entering a system through the electrical outlet.
There are various types, and they usually provide a level of protection commensurate
with their cost. Some also provide warranty coverage for certain types of damage.
Compare joule ratings to determine the relative effectiveness of different devices.
Most surge protectors do not protect against lightning strikes, so you should dis-
connect your computer when lightning is near.
Modems can also be damaged by power surges on telephone lines and should be
disconnected during electrical storms. Many surge protectors have a phone jack for
modem protection. Network connections cannot be protected by surge protectors.
Therefore, always disconnect the network cable from the network card connector
during electrical storms.
Surge protectors do not offer protection against brownouts, which occur when the
voltage drops more than 20 percent below the normal AC line voltage level.
Line conditioners keep a computer's AC power source voltage at a fairly constant level
and, therefore, can handle brownouts. Because of this added protection, line condi-
tioners cost more than surge protectors—up to several hundred dollars. However,
these devices cannot protect against a complete loss of power.
A power loss while your computer is writing to your hard-disk drive can result in loss
of data and file corruption. Worst case, your operating system could be corrupted.
An uninterruptible power supply (UPS) offers the most complete protection against
variations in power because it uses battery power to keep the system running when
AC power is lost. AC power, while available, charges the battery; when AC power is
lost, the battery provides power to the system for a limited amount of time—from
15 minutes to an hour or so—depending on the UPS system.
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