I installed it on my sony vio laptop and everything works fine, can you give a little more specs on your setup so I can get an idea on what might be causing this problem. Can you use the FN key if you boot to a command prompt using a dos boot disk, if you can us the FN Key for sound and brightness then the problem is with the OS if it can't be used then you've got a problem with your setup. If it is with your OS try going in device manager and changing the keyboard type, it'll allow you to search or select from a list (think its called advanced) and select the sony driver if one is available, if not just try removing it and rebooting allowing it to redetect the keyboard. Beyond that you might have to wait for driver support from sony.
 
Good Luck
PrinceAli0

I have the same notebook, running XP final, What did you guys do in regards to the software/drivers seeing sony use a really shitty method of distributing software on their CD's? I tried using the win2k drivers on their site, but most of the installs just hang while inspecting my system. Secondly, my machine will not reboot. Any experience with this?