I have replaced my old 4 speaker system with a Logitech z506 system.I can only get sound from the sub and the four single speakers or the sub 2 spakers and the central speaker. I have tried all configs of conection to no avail , all speakers work but only get play from two ports in the back of the tower and i need 3 any ideas.PLEASE

Is the onboard sound card being used or a separate card? If you have both, do you have the same issue with both the onboard sound and card?

Hi, I have checked the compatibility center but cannot find your Speakers. Please confirm with Logitech if it is compatible with Windows 7. I notice it uses the native USB drivers. Therefore, you can try different USB ports to check the result. If possible, test the issue on another computer. I suggest updating BIOS and reinstalling USB controller to check the result. http://blogs.technet.com/b/asiasupp/archive/2010/11/23/error-message-one-of-the-usb-device-attached-to-this-computer-has-malfunctioned-and-windows-does-not-recognise-it.aspx Also check the USB filter driver in registry. 1. Click the Start Button, type "regedit" (without quotation marks) in the Start Search box and then press ENTER. 2. Navigate to the following key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{36FC9E60-C465-11CF-8056-444553540000} 3. Right click the {36FC9E60-C465-11CF-8056-444553540000} entry, choose "Export", select Desktop in the Save in box and type backup in File Name. Click Save. Please Note: The backup file is on the Desktop and named backup.reg. We can simply restore the registry by double-clicking the backup.reg file. 4. Highlight this key ({36FC9E60-C465-11CF-8056-444553540000}), on the right pane, delete the upperfilter and lowerfilter entries if these strings are present. 5. Restart your computer in clean boot and check if the problem disappears. Meanwhile, please contact Logitech to check its configuration. http://www.logitech.com/en-us/speakers-audio/home-pc-speakers/devices/7191 Note: Since the website is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information. Best Regards, Niki Please remember to click "Mark as Answer" on the post that helps you, and to click "Unmark as Answer" if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.