Enable F1-F12 keys without Fn on Lenovo Ideapad S400u

Shortest answer is the best ..Lenovo website community

Solution! Betreff: T440 - Reverse FN Key Options ‎02-02-2014 03:05 AM

just press "FN + ESC" once. There you'll have your single press F1... keys working.. 2 person found this solution to be helpful.

Now the light is on and then you can for example press the brightness,audio etc without pressing fn every time

I think the Lenovo IdeaPad S300/S400/S400u/S405 User Guide V2.0 (pdf) has what you want on page 12 in Chapter 2. Learning the basics where it says:

• Setting hotkey mode
  
  By default, the hotkey functions are accessible by pressing the appropriate hotkey. However, you can disable the hotkey mode in the BIOS setup utility.
  To disable the hotkey mode:
  
  
  1. Shut down the computer.
  2. Press the Novo button and then select BIOS Setup.
  3. In the BIOS setup utility, open the Configuration menu, and change the setting of HotKey Mode from Enabled to Disabled.
  4. Open the Exit menu, and select Exit Saving Changes.

_{Note: When hotkey mode is disabled, press the Fn key and the appropriate hotkey to access the corresponding hotkey function.}

There is a new BIOS update from Lenovo company. The problem was solved:

Symptom
Some models of G/Z/P Series cannot achieve traditional function by pressing F1 to F12 directly.

Affected configurations
The above symptom may occur to the following systems:

• Lenovo G400\G500 with BIOS versions lower than V2.01
• Lenovo G405s\G505s with BIOS versions lower than V2.03
• Lenovo G400s\G500s with BIOS versions lower than V2.02
• Lenovo Z400\Z500\P500 with BIOS Versions lower than V1.21
• Lenovo G405\G505 with BIOS Versions lower than V2.04
• Lenovo G410\G510 with BIOS Version lower than V2.01

See the above link for downloads. It says win8 but it's working in all windows versions.