Windows 7: I can't unmute my speaker

my speaker is always mute. I use netbook hp mini210. I always use quick key (f11) if i want mute or unmute my speaker. but now if i press the button, speaker is still muted. whats happen? is this virus? please help me.

Check all of your settings by
clicking the volume button in the notification area:

Left Click volume icon
Click the speaker which appears at the top of the mixer
Click properties in the controller information section
Check that the device driver is working as required (update of reinstall if required)
Close the window
Back in the speaker properties -> Click on the levels tab
Ensure that your devices level is set at 100 and not muted

Have you noticed anything at all which happens if you press the F11 key
and have you recently made any changes in the BIOS of your machine?

I am asking this because the F keys have different functions depending
on how they are set on particular models within the BIOS (advanced options).
As an example, with your model if these settings are changed, then hitting
F11 will minimise and maximise your web browser instead of being for volume adjustment
which would then become FN + F11

Check this link for more info:
Disable The Fn + Function Key Combination on Certain Models - HP Customer Care (United States - English)

Good luck

I was do that. and device is working properly. i think the problems is not at the button(f11). because i also can not play the mp3. usually if my speaker mute i still can play the mp3. and the lamp at the button(f11) is always turn on

I don't mean this to be offensive in any way but I am having a little trouble with
the way you are describing things in broken English. As I said - absolutely no
offense intended.

With that being said, are you now saying that the device is working properly
and as you want it to?

If this is not the case and you still have the problem, try these things
in the following order:
1) Uninstall the sound card driver and re-install:
Click start button (Windows orb)
Click Control Panel
Click Device Manager
Expand Sound, Video and Game Controllers section (use small arrow next to heading to expand)
Right click your audio device/ s and select uninstall to remove the drivers from your system
Reboot the machine
Your system should report that it finds the device and will install driver/ s for it/ them
Follow the prompts and reboot again if required

2) If for some reason the system is unable to find and install the drivers for your machine automatically then try using the following link to search the manufacturers website for your particular model (follow this link to see how to check the model number, operating system and the associated drivers:

Locate the Notebook Product Number or Serial Number HP Mini 210-1006TU PC - HP Customer Care (United States - English)
(How to check the model number of your HP - use above link)

HP - Australia | Laptop Computers, Desktops , Printers, Servers and more (HP Support - click on the support and drivers link at the top of the page. You may also need to Google to see if your particular country of origin has a support site if your model cannot be searched through this link)

Note that you may also need to uninstall and re-install the quick keys/ quicklaunch driver

Hope this may be of some use to you

haha sory if my english language not good.but thank you for your info. problem is solved.