By now, a number of tech savvy folks would have upgraded to Windows 10. If you have a problem with your brightness control after upgrade of after any update, your solution is here.
Windows 10 is in its very early phase and updates are still applying bug fixes and internal modification. However, its a very good Operating System which is very fast to use. I actually love Windows 10 and would advice to upgrade if you have not.
If you have an unresponsive brightness control/button after upgrade, this is not a problem. Its very easy to solve.
All you need is to reinstall your Graphics Driver
For intel Processors 32 bit, Click Here to Download Graphics Driver
For intel Processors 64 bit, Click here to Download Graphics Driver.
For AMD Processors, Click Here to Download Graphics Driver