Dell Precision T7400 (Late 2007) - Manual (Page 170)

170 Adding and Replacing Parts
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. 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 and reset the configuration options.
Removing the Battery
1 If you have not already done so, write down your configuration information
found in system setup (see "System Setup" on page 75).
2 Follow the procedures in "Before You Begin" on page 139.
CAUTION: Your computer is heavy (it has an approximate minimum weight of 55
lbs) and can be difficult to maneuver. Seek assistance before attempting to lift,
move, or tilt it; this computer requires a two-man lift. Always lift correctly to avoid
injury; avoid bending over while lifting. See your
Product Information Guide for
other important safety information.
CAUTION: The computer stand should be installed at all times to ensure
maximum system stability. Failure to install the stand could result in the computer
tipping over, potentially resulting in bodily injury or damage to the computer.
3 Remove the computer cover (see "Removing the Computer Cover" on
page 141).