have you tried re-tasking your jacks?
please view here:
http://www.intel.com/support/motherboards/desktop/sb/CS-020642.htm#6ch
Some Speakers Don’t Play?
If you can hear sound coming from some speakers, but not others, check the following:
The system may assume you are using two-channel (stereo) sound, even if you have plugged in four or more speakers. Select the correct speaker type with the Windows Speaker icon or the third-party sound mixer you’ve installed.
* The speakers may be connected to the wrong jacks. Make sure you connect all speakers to the correct jacks. If you connect them to line-in or microphone jacks, they won't work. Refer to the documentation that came with your speaker system for connection details.
* The balance settings may be incorrect. If you hear audio from the left speakers only or the right speakers only, check the balance. Balance control needs to be centered with the Windows Speaker icon or a third-party sound mixer.
* Some 4.1 speaker systems (one subwoofer and four satellite speakers) are designed to connect to computer gaming sound cards. If you connect to a standard computer sound card (or onboard audio) instead, look for an input switch and make sure it is set to ‘stereo’. Consult the documentation for your 4.1 speaker system for more details.
* It is common to hear only front right and front left channels from a multichannel receiver when it is connected to S/PDIF. If your receiver has discrete multichannel analog connections, it is recommended that they be connected to the Analog Front-Out, Rear-Out, and Center/Subwoofer Out.
On some systems with integrated audio, audio jacks have multiple uses. For example, in six-channel mode on some systems, the normal line-in and microphone jacks might be reconfigured to work with rear and center/subwoofer speakers. In such cases, the mixer controls need to be reset.
if the above didnt help.please check your system for the latest driver.
http://www.intel.com/support/motherboards/desktop/detect.htm
