Sony PCG-XG28 Primary User Manual page 54

When the computer is on, be sure to follow the steps below, otherwise the
system may not activate properly. When the computer is off, skip steps 1
to 4.
Click the Start button, point to Setup, and then click Control Panel.
Double-click the PC card icon.
Click the name of the PC card you want to remove from the list that
displays, then click Stop.
When the message "You can remove the PC card" appears in the
display, click OK.
Press the RELEASE button to remove the PC card.
Insert the PC card slot protector back into the empty slot.