Fn key will not work on Acer Aspire 5742z! with internal or external keyboard

[otherdreams]

I have an Acer 5742z laptop with a perfectly functional keyboard, except that the Fn function key has stopped working.

These are the steps I have tried:

--Replaced the keyboard with a known good spare from my old 5742z.

--Tried an external USB keyboard.

--Tried the Windows On-Screen Keyboard and online keyboard testers. None register the Fn key with internal or external keyboards.

--Checked BIOS for a "Fn Enable/Disable" option. Did not find this option...?

--Updated my BIOS from V1.16 to V1.30.

--Uninstalled and reinstalled the Dritek/Acer Launch Manager utility.

--Checked Task Manager to see that Launch Manager is running.
(Processes LMmanager, LMworker, MMDx64Fx, Dritek WMI Service are all running from the Program Files (x86)/Launch Manager/ directory.)

--Tried switching all of these processes to Run As Administrator and to Vista Compatibility.

--Loaded ALL startup programs in msconfig. (Dritek Launch Manager was listed there.)

--Switched the Keyboard Device Driver to an incorrect PS/2 driver and then back to the Standard PS/2.
(Is there a better driver for this keyboard??
https/ae01.alicdn.com/kf/HTB16roubRfM8KJjSZFhq6ARyFXaf/OEM-US-Layout-Keyboard-Replacement-for-Acer-Aspire-5742-5742G-5742Z-5742ZG-5745-5745G-5745P-5745PG.jpg )


...all without success!


What is left?
I don't think it's hardware, so somehow the key is disabled in firmware or OS?
Maybe I need new keyboard drivers?
Or...?

This has been driving me crazy for months. Please advise.
Thank you!

 

[Lutfij]

Speaking of OS, what are you working with? Since when did the issue crop up? You could try and use keyboard tester to verify if the keyboard itself isn't registering a keypress. You might also want to inspect the ribbon cable with which it connects to your laptop motherboard.

 

[otherdreams]

Speaking of OS, what are you working with?

Thanks for the reply Lutfij!
I'm using Windows 7 Home Premium 64-bit.

You could try and use keyboard tester to verify if the keyboard itself isn't registering a keypress. You might also want to inspect the ribbon cable with which it connects to your laptop motherboard.

I do not believe it is the ribbon cable because I have tried two different internal keyboards plus one USB external keyboard. None of them have a Fn key that registers with online keyboard testers or OSK.

Since when did the issue crop up?

The issue started several months ago. First I lost some Fn functions and then all of them.

Perhaps something like ComboFix scan could have inadvertently knocked out a critical component. Also I periodically disable windows startup programs and services..

Launch Manager uses msiWMI service, but when I look at that services properties it says it has no dependencies and depends on no other services or processes. .
Could the Launch Manager processes have lost their connection to Launch Manager services ?

 

[otherdreams]

Any ideas?