Acer Travelmate 4060 ZL8?
Look like this?http://www.ebay.com/itm/Acer-Travelmate-4060-Series-ZL8-PM-1-73Ghz-512Mb-Laptop-/310359835033
IF so, this is Acer Support > Acer Travelmate 4060 series > Drivers and Downloads page,http://support.acer.com/us/en/product/default.aspx?tab=1&modelId=232
Your audio (Sound) driver file/s are corrupted. Some information is missing.
Download AND install the Audio driver.
[ Corrupted file. In this case an audio driver file.
The information on a harddrive is stored in files. Think of them as books on a bookshelf at a Library.
More than likely Windows has lost the Address to the files.
This would be akin to losing which bookshelf the books are on, at the Library.
When you install the Audio driver file from Acer Support, it will repair, or replace the existing corrupted audio driver file/s.
There is only one Audio driver file listed.
You can see the vendor is Realtek. This means Realtek made the audio chipset, that is used on your laptop.
[ Chip and Chipset are slang terms for I.C.
Click on either Audio Driver in blue, or the white arrow in the green circle icon, under Download at the far right.
A small window will come up on the right;
Make sure there is a green dot in the small circle, to the left of -
If not, click in the small empty circle to the left of Save File.
Now go below, and click on OK.
A small window will come up on the left.
In the wording in the heading at the top of the small window, tells you where the file will download to.
Write it down.
In the wording may be Desktop, or My Documents, or Downloads.
Desktop: The audio driver file will download to your desktop screen.
My Documents: Click on Start, then My Documents.
Downloads: Click on Start, My Documents, then Double-click on Downloads.
When you see the audio driver file Double-click on it.
The Unzip wizard will appear.
Click on - Unzip.
Now go to the far left side - Top, and click on Extract all files.
Tell me what you see. Driver files differ. It may have an Execute file to click on, (.exe), or a different file. OR, it may start the Installation Wizard.
If the Installation Wizard comes up, just click on Next, Next, and Finish, at the bottom of each small window.
(Windows knows the proper place to put the driver file.
In the second small window, you will be shown various places you can Manually select.
DO NOT click on anything but Next, and Finish at the bottom )
IF, you are not asked to Restart your computer, do so.
Close all windows, go back to your desktop screen, and restart the computer.
[ Click on Start, Turn Off Computer, then Restart ]
Have your speakers turned down.
Post back in a Comment as to your findings.