I have T500 type 2083 a15 W7 32 bit Professional (refurbished machine) and I cannot adjust the screen brightness despite me pressing Fn and Home/ End. It brings up the bar display but does not effect any change, even when I try adjusting the levels (the bar shows this happening).
Also, when trying to find brightness control via the Windows control panel and then display settings, control is not available.
Note: I have downloaded and installed all the current recommended updates.
The following is a checklist of things you can do to bring back screen brightness control on your T500, as shared by our community members:
1. Check if all other hotkey functions work, such as Volume and Thinklight
2. Get the Lenovo ThinkVantage System Update utility if you don't have it - it's to check if BIOS update is needed.