I may need to replace the internal battery on the following Notebook:

Sony
VAIO
Model PCG-FX240 •
Pentium III • 800 MHz
• Hard Drive 15 GB •
Ram128 MB •

This is all the info from the user's guide:

My notebook starts, but a BIOS error is displayed.
When the internal backup battery is low on power, it may not start your
system properly. The message “Press <F1> to resume, <F2> to setup”
appears at the bottom of the screen. Follow these steps:
1 Press F2. The BIOS Setup menu appears.
2 Set the date (month/day/year). Press Enter.
3 Press to select System Time, then set the time (hour: minute:
second). Press Enter.
4 Press to select Exit, then press to select Get Default Values. The
message “Load default configuration now?” appears.
5 Select Yes and press Enter.
6 Select Exit (Save Changes), and then press Enter. The message “Save
Configuration changes and exit now?” appears.
7 Select Yes, and then press Enter. The notebook restarts.



Can any of you point me to some step by step instructions to replace that battery??