Which operating system ?
XP If your computer came with a motherboard disc the sound drivers could be on it Click start control panel administration tools computer management device manager scroll to sound video and game controllers you might see a yellow question exclamation mark? ! or a red X Right click to reinstall drivers Click start control panel sounds and audio volume advanced speakers make sure you have selected the (appropriate speakers) also audio you will find 3 drop down lists make sure you have the selected correct speaker settings there Click start control panel sounds and audio devices select advanced there might be a tick in the mute box untick it if his does not fix the problem Click start control panel sounds and audio devices you can adjust the volume there also select speaker

volume you can change your settings there you can also tick in the box place icon in taskbar for any

further volume control settings you will need to right click on the speaker volume icon system select adjust volume Click start control panel sounds and audio volume advanced speakers select the appropriate speakers from the drop down list or navigate to the device manager scroll to system devices + to expand system

speaker right click properties then select use this device (enable) also you might check the speaker plug/outlets is usually at the back of the computer you will have to open up the computer to check the lead attached to the rear of the input plug make

sure the connection is good with no dust as dust causes static electricity clean your computer of dust using a fine air blower from a compressor making VERY sure that there is

no MOISTURE in the air line or use a can of compressed air specifically around the sound card and the CPU central processing unit

dust causes static to build up in a computer W7 click start right click on computer select properties then device manager scroll to sound and video game controllers if you see a yellow question/exclamation mark or a red X the driver will need to Click start control panel hardware and sound manage audio devices right click on your speaker select configure speakers right click on the speaker icon in the bottom taskbar you will see an array of options select playback devices make sure it has a green tick and the correct speakers are selected be updated if you computer came with a motherboard disk the drivers could be on it although once speakers are connected widows 7 should automatically update the drivers Click start control panel hardware and sound manage audio devices playback you might have to set a default go for via high definition audio then right click on speaker you might have to configure them then select properties you will see tabs general level in this tab make sure your settings are loud enough also enhancements and advanced from the drop down list in the advanced tab select dvd quality or another then apply Hope this helps.