Sony PCG-TR5MP Hardware Manual page 21

Hardware Guide
To remove the battery pack, proceed as follows (PCG-TR series):
1
Turn off the computer and close the cover.
2 Slide the lock lever (1) to the Unlock position.
3
Slide and hold the release lever (2) as indicated and slide the battery away from the computer.
✍
You can remove the battery pack without turning off the computer if it is connected to the mains voltage (AC adapter).
Close the cover before you remove the battery pack.
You may lose data if you remove the battery pack while the computer is on and not connected to the AC adapter or if you remove the battery while the computer is in Standby
mode.
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20
Using your VAIO computer