Dell Precision T3400 (Late 2007) - Manual (Page 249)

Adding and Replacing Parts
249
CAUTION:
A new battery can explode if it is incorrectly installed. Replace the
battery only with the same or equivalent type recommended by the manufacturer.
Discard used batteries according to the manufacturer’s instructions.
NOTICE:
To prevent static damage to components inside your computer, discharge
static electricity from your body before you touch any of your computer’s electronic
components. You can do so by touching an unpainted metal surface on the
computer.
About the Battery
A coin-cell battery maintains computer configuration, date, and time
information. The battery can last several years.
The battery may need replacing if you have repeatedly reset the time and date
information after turning on the computer or if one of the following messages
appear:
Time-of-day not set - please run SETUP program
or
Invalid configuration information -
please run SETUP program
or
Strike the F1 key to continue,
F2 to run the setup utility
To determine whether you need to replace the battery, re-enter the time and
date in System Setup and exit the program to save the information. Turn off
your computer and disconnect it from the electrical outlet for a few hours;
then reconnect the computer, turn it on, and enter System Setup (see
"Entering System Setup" on page 81). If the date and time are not correct in
System Setup, replace the battery.
You can operate your computer without a battery; however, without a battery,
the configuration information is erased if the computer is turned off or
unplugged from the electrical outlet. In this case, you must enter System Setup
(see "Entering System Setup" on page 81) and reset the configuration options.
Removing the Battery
If you have not already done so, make a copy of your configuration
information found in System Setup (see "System Setup" on page 81).