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I have just purchased the S405. The machine came with Win8, and seeing that I was uncomfortable with the Win8 OS. I decided to do a clean install of the Win7. However after updating all the drivers I noticed that the display seems to be dimmed even when it is maxed out.


When the machine was running on Win 8 everything seems to be fine. I believe this could be the effect of a Win7 driver. Could there be a driver I'm missing ?



The BIOS implementation on the S405 was originally  developed with Windows 8 preload in mind, and not with formal support for Windows 7 downgrade or clean installs.  (Windows 8 supports 101 levels of screen brightness, while Windows 7 supports only 16)  As a result, screen brightness of about 50% of max are likely to be experienced under Windows 7 on this system.




A BIOS update to version 8.05 or later should improve brightness under Windows 7

Here is a link to the BIOS update


A formal tip on our support site is available here that explains the original constraint:




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I get this problem after trying to install updated display drivers under Windows 8!!! How do I get the brightness back?!? Once again, this is happening under Win 8 after a driver update, trying to install original drivers which came with the PC does not help...

I found that updating the bios to 8.05 solves the brightness problem. After updating my S405 the screen is much brighter and the keyboard controls work well. The bios files can be found on the Lenovo website at:


Thanks Chris!




Try to uninstall the video drivers and then update to the ones on our support site, along with hotkey and any power management drivers which may be available.


Check out some of the comments in the related forum discussion here for Windows 8 / 8.1 to resolve brightness issues.