I recently bought a ST4120p on eBay, which had some problems to get Windows XP and all the Fujitsu drivers installed (some faulty hardware inside had to be swapped out).

It now works well, with one exception: I discovered I cannot change the screen brightness. The digital manual says to press the FN key twice (which I understand is the bottom key in the top row -- I use my tablet in portrait mode only) to access the brightness control, but no matter how I double-press that key, nothing happens other than the hard disk light blinking twice.

I'm assuming some driver wasn't installed, but I dare not mess with this thing again unless I know a lot more about it. Also, my relationship with the seller has dropped to a temperature level that's more appreciated by superconducting experts (it's not good anymore).

Does anyone know a solution to this? A link to a separate brightness control program would be neat, as I'm really afraid to mess with those Fujitsu drivers.