I'm using Windows 7 Home Premium, on laptop Acer 7740g with the latest Catalyst drivers.
From time to time, the brightness adjustment stops working, by using the FN keys, neither by manually adjusting it through the Power Options. I think it happens sometimes after my PC comes back from sleep, but not sure. Restarting the PC solves the issue, but I don't like restarting.
If you're not familiar with the problem, maybe you can perhaps tell me, which service is responsible for the brightness adjustment? this way I can at least restart it..