From a post by whest and vanq69 (thanks as this also works for the VGN TX3)
Use compatibility with vista to install the program if it wont install -
To install a driver OR program in compatibility mode - right click the setup.exe file - click properties - click compatibility - check run in compatibility with vista/xp etc - check run as administrator - leave the rest blank. Start setup.exe and install.
I went to:
Vaio : Sony Europe (url - Vaio : Sony Europe
From this I downloaded and installed in the following order (all were just the 32bit versions but worked for me):
SFEP Driver (installed through Device Manager)
Sony Shared Library
Setting Utility Service
VAIO Event Service
-- Should now have function and S1 button working
VAIO Power Management
VAIO Control Centre.
After several reboots it worked !!
Hope this helps anyone who has the same issue. I will re-iterate this worked for me for my model but hopefully this might provide a starting point or solution for others. Many thanks to Whest for his invaluable help.
Thanks to the other posts I have fixed the problem.