I have a eee PC Asus netbook. Some function keys such as F10 for mute, F11 decrease Sound and F12 increase Sound, doesn't work. Other keys with Function key, work properly.

I have an ASUS laptop and I use fn f11 for volume down, fn f12 for volume up, and fn f10 for mute.
fn is the function key and is found on the left bottom of the keyboard between the ctrl and windows keys.

Are you pressing the fn key at the same time? These are FunctioN buttons and work in conjunction with the fn key.

1 - Function Keys f1 through f122 - Configurable Function key fnDisable fn in the BIOSTo disable, or enable, the function key (fn) in the BIOS, do the following steps.

1. Press the power button to turn on the computer.
2. Press the f10 key to open the BIOS setup window.
3. Use the right-arrow or left-arrow keys to navigate to the System Configuration option.
4. Use the up-arrow or down-arrow keys to navigate to the Action Keys Mode option, and then press the enterkey to display the Enable / Disable menu.
5. Select the desired mode:
   • Disabled : Requires pressing fn key + f1 through f12 to use the action as indicated on the action key.For example, if Disabled , pressing fn + f11 will mute the sound as indicated on the key on this model PC. Alternatively, pressing f11 only will minimize and maximize a web browser if open.The action keys may vary depending on the model of notebook.
   • Enabled : Requires pressing only f1 through f12 to use the action as indicated on the action keys.For example, if Enabled , pressing f11 only will mute the sound as indicated on the key on this model PC. Alternatively, pressing fn + f11 will minimize and maximize a web browser if open.The action keys may vary depending on the model of notebook.
6. Press f10 key to save the selection and restart the computer.

The function key (fn) option can be reset at any time.

The laptop keyboard needs to be replaced, go to www.ebay.com Type: make and model of laptop and refine search to keyboard.

The uses for the function (f1-f12) keys varies based on which program you have open at the time. Different programs use them for different things.

However, your computer also has some default uses for these keys when combined with pressing the fn (function) key.

fn + f1 locks computer

fn + f2 changes our power use profile

fn + f3 puts the computer to sleep

fn + f4 puts the computer into hibernation mode

fn + f5 changes the display/output mode

fn + f6 decreases the screen brightness

fn + f7 increases the screen brightness

fn + f8 enables/disables wireless connections

fn + f9 enables/disables the touch pad

fn + f10 turns the cursor overlay on/off

fn + f11 turns the numeric overlay on/off

fn + f12 turns scroll lock on/off

The Function keys serve various functions for various programs and with laptops, in combination with the Fn key, the function keys have additional functionality such as increasing or decreasing illumination of the screen, mute on/off, touchpad lock/unlock, switch from external to internal monitor and so on. These special functions are labeled onto the keys themselves.
Here's a short list of what function keys do in various programs:

F1=Help
F2=Rename Desktop Icon
F3=Find
F4=Address Bar Autocomplete
F5=Refresh(on a webpage)
F6=Move cursor in structure (Address-Tool-Web)
F7=Caret Browsing
F8=Enter Safe Mode (while booting)
F9=Update selected text (MS Word)
F10=Menu Bar (MS Word)
F11=Full Screen
F12=Developer Tools
For a more detailed list of functions, take a look at this website http://www.computerhope.com/issues/ch000306.htm

http://www.netbook3g.com/wp-content/uploads/2009/01/asus-eee-pc-900hd-900ha-keyboard-t.jpg

F1: sleep
F2: Wifi
F3; lower brightness
F4: higher brightness
F5: switch to external monitor
F6: uhh not sure... stock market? lol
F7: mute
F8: Down volume
F9: Up volume
F10: F10
F11: Num Lock
F12 Scroll lock

Fn + F1 Change Display Device. Fn + F2 Wireless Control Fn + F3 Battery information Fn + F4 Decreases brightness on the integrated display only (not on an external monitor). Fn + F5 Increases brightness on the integrated display only (not on an external monitor). Fn + F6 Keyboard backlit(available only if a backlit keyboard is installed) Fn + F7 Mute Fn + F8 Decrease audio Volume. Fn + F9 Increase audio Volume. Fn + F10 CD Previous - Play previous media file. Fn + F11 CD Play/Pause - If there is Audio CD in system, Media player will play music. Fn + F12 CD Next - Play next media file.

HI,

You might have to install the fn keys drivers once again.

Use your ASUS Probe (I think this is it) software to update the BIOS and see if it helps.

Rate me as fixya if this works.