NEC VERSA FX Service And Reference Manual page 26

Replace the battery pack installed in your NEC Versa system as follows.
Note
Use the batteries in the NEC Versa computer for which they are designed. Installing
another manufacturer's battery, or using a combination of very old and new batteries can
deteriorate battery and equipment performance.
1. Save your files, exit Windows, and turn off system power.
Close the LCD panel and turn over the system.
2.
3. Slide the battery release latch toward the right side of the system and hold firmly.
A – Lithium-Ion Battery
2-6 System Configuration and Setup
Locating the battery bay release latch
B – Battery Release Latch