Whenever viewing a video using Internet Explorer, or downloading a video and playing using Windows Media Player there is no sound. The sound on the computer itself appears to work, as I can use iTunes to play CDs without any problems. The computer is running Windows XP.

This is an interesting problem, as most people in a similar situation have the opposite issue – they get sound but no video. In that instance, the most common explanation is that the video codec for the file being played is not installed on the computer. The codec allows the computer to decode and playback the format of video contained within the file. Without the codec, the computer does not understand how to decode the video and thus cannot display the video. There are also audio codecs which can decode the audio track within videos, and if this was not installed then the computer would be unable to play the audio for the video. However, this is a relatively unlikely cause of the problem. From your description of the problem, the problem is experienced when playing videos in Internet Explorer or Windows Media Player. As such, I assume that you are attempting to play videos in the Windows Media formats (e.g. asf, wmv, avi) as these formats are supported by Windows Media Player. Additionally, when you attempt to view one of these formats within Internet Explorer it actually launches Windows Media Player within Internet Explorer to playback the files. As you can see, Windows Media Player is used no matter which method you use to playback the videos (i.e. within Internet Explorer or downloading the videos and playing through Windows Media Player natively). Therefore, the problem is most likely related to Windows Media Player not correctly playing back audio.

As a test, we need to determine whether the problem specifically occurs when Windows Media Player is used to playback video, or whether the problem also occurs when playing back other file formats, such as pure audio files. Open Windows Media Player and then go to the “File” menu > “Open”. If the File menu is not visible, press the Alt key on your keyboard to trigger the menu. Go to your “My Documents” folder and open “My Music”. Within this folder you should see a folder called “Sample Music”. Open this folder and then double-click to open and play one of the files contained within. Ensure that the volume is set at a reasonable level so you can hear the audio. Should the audio not be heard, it seems there is a problem with Windows Media Player itself not playing back audio in general, regardless of file format. This will be a difficult problem to diagnose, since Windows Media Player inherits the default audio playback settings of Windows, so there are no settings within Windows Media Player which could be causing the lack of audio playback. The best suggestion in this situation is to ensure you are running the latest version of Windows Media Player. Open Internet Explorer and go to Windows Update (windowsupdate.microsoft.com). This will automatically scan your computer and suggest the updates which need to be installed. If you are running a fairly old installation of Windows XP which has not been updated in recent times then it is likely that you will have a dated version of Windows Media Player. The advantage in updating is this should fix any problems with the current installation. However, should you find that updating Windows Media Player does not fix the problem then it may also be worthwhile running the System File Checker utility. This will scan the computer and look for any missing or corrupt files, replacing these with known good copies. To start the System File Checker go to the “Start” menu > “Run” and type “sfc /scannow” (without the quotes) and click OK. The System File Checker will automatically commence operations. Once it has finished it will close silently with no feedback. Once this has happened restart the computer and check whether the problem still exists.

The second scenario which we will consider is where other audio files play correctly within Windows Media Player and the lack of audio problem is limited to playing video files. A possible reason for this happening is there is a piece of software installed on your computer which is conflicting with Windows Media Player. I have seen situations where DVD ripping (copying) or other video-related software on the computer conflicts with the codecs used in Windows Media Player and results in audio (and in some situations, video) not playing. If you have recently installed any such software on your computer, about the time this problem first occurred, then try uninstalling the software to see whether that resolves the problem.

Should you uninstall the software and the problem continues, or you did not have any such software installed in the first place, then some users have reported this problem can be fixed by installing some additional audio codecs. While this should not be necessary, as the audio codecs should come installed with Windows Media Player, this may help resolve the problem. AC3Filter is a free audio codec for Windows which has been reported to fix the problem by people in similar situations. You can download AC3Filter from ac3filter.net/project/1/releases . Once installed restart the computer and check whether it has resolved the problem. If this does not resolve the problem, another codec set I recommend that you install is FFDshow. This is available for free download from: www.afterdawn.com/software/video_software/codecs_and_filters/ffdshow.cfm/rev__610__20061201 and allows the playback of various other types of video and audio files. Again, once you have installed FFDshow, restart the computer and check whether the problem continues.

If you reach this point and you have not been able to resolve the problem then you may need to contact me again for further advice. In the meantime, if you urgently wish to play some of the videos, you could try VLC Media Player (www.videolan.org). This is a free, open-source media player which can play practically any video or audio file types. Should you wish to use VLC Media Player then you will need to locally download the video files to your computer and then open them using VLC. It will be a difficult process to setup VLC to automatically play streaming videos through Internet Explorer so this playback option will not be possible at least for the moment.