Its always worked in the past but all of a sudden its died.

So now I cant quickly change volume, brightness etc by holding the Fn button with another.

Sony Vaio laptop PCG-V505M

XP Pro

Any advice would be greatly appreciated?

Try on screen keyboard yet??? Programs--->Accessories---->Acessibility

I've just discovered that both Fn buttons work with the arrow keys for Pg up and down etc. but not with the F keys to alter vol, bright etc.

The same happens through the on screen keyboard.

Just to clarify - The F keys are working its just Fn & F keys that aren't.

Anybody with any last minute advice before I take it over to the Sony hospital?

I might be a hot key driver issue, on my toshiba they call EZbuttons. I'd be willing to bet there is some OEM software/drivers you need to re-install to get volume & brightness functionality working again. Have a look on the sony support site, there's probably something there you can download to re-install this functionality if you don't still have your original CD's.

As PomThai says above, if this model is like my other Sony's there are a set of programs, usually on the install CD which you may need to reinstall. These invoke the specific Functions, such as screen brightness, switching monitors etc. which are not part of the standard key-mappings.

Sony used to provide links within their sites, might be worth checking, though if the product was not shipped to a default English locale then the pages may only be in Japanese.

Regards

/edit typo //