Sony PCG-N505VE - Manual (Page 29)

Using the Keyboard 19
Replacing a key top
If the enter key or the space bar key comes off, replace the key top in the
position shown below. If any other key top comes off, replace it in its
original location and push it down until it clicks.
To replace a key top
Remove the wire from the key top, then attach it to the hook on the unit.
Align the center of the key top and press it from the top.
Enter Key
Space key
Wire Hook