i really don't know what caused the problem. My browser cant anymore play sounds/music, like in youtube. i can see it playing. but there's no sound. During the my windows startup, there's nto starup sound anymore. I tried using other browser like firefox, no effect. i've downloaded the shockwave player and the latest flash player still no effect. But when i try to play music from media player, and itunes. it played. Anybody here who could help me please.

Some of these may use Quicktime video, download the latest version of the Quicktime player here
That may solve your problem, although it depends what media YouTube use. Check all of the volume options on the task bar and in the control panel.

Sometimes it's simply that your speaker plug has pulled out (partially or completely).
Some computers have their sound card integrated on the mother board. Double check to see if something didn't go wrong with the sound driver. You should have a disk of drivers that came with your MB. You can try re-installing the sound driver.

Windows Essentials Codec Pack = http://www.pcworld.com/downloads/fil...l?tk=nl_wbxdwn + http://www.mediacodec.org/
Combined Community Codec Pack = http://cccp-project.net
K-Lite Mega Codec Pack = http://mirror.edskes.net
http://www.free-codecs.com/download/...Codec_Pack.htm
K-Lite Codec Pack Standard 2.77 = http://majorgeeks.com/download.php?det=4620
codec's for avi mpeg2 = http://www.wmplugins.com/ItemList.aspx?typeid=8
http://avicodec.duby.info
http://ffmpegx.com/index.html
GSpot can be used to determine if any additional codecs are needed and if they are installed on your system. = install GSpot, launch it and drag 'n drop the WMV file into the GSpot application window. = http://www.headbands.com/gspot
info on troubleshooting WMP11, here,
http://www.microsoft.com/windows/win...eshooting.aspx

FAQs http://www.microsoft.com/windows/win...q/default.mspx

I've found two possible fixes for your problem.

Check the audio tab and the sound playback tab in control panel under sounds and audio devices and the volume tab. Default device may be set to the wrong device. It should be the sound card that you have in your system. When you have correctly identified the correct sound card please press apply after selecting it. This may fix your problem.

Here is another solution that may help you.

Opened Administrative Tools/Services
Clicked on the "Standard" Tab
Scrolled down to the "Windows Audio" service.
Guess what, The Windows Audio service was Disabled!!!
I double clicked on the Windows Audio service.
I changed the "Startup type" from "Disabled" to "Automatic"
In the Service status section I clicked "Start"
The Windows Audio service started.
I opened Control Panel and dbl clicked on Sound and Audio Devices.
Device volume and Speaker settings were no longer greyed out.
All windows sounds were restored.

These were on another site found with google, hope this helps.

hey thanks for all your help everyone!

No Worries, that's what we are here for!