I have recently built a new system with the Asus P6T SE as the motherboard with the latest chipset installed. I had been using a G9 Logitech mouse (USB device), a Logitech Classic Keyboard 200, and a Microsoft LifeCam VX-5000 without any trouble at all (all devices with latest drivers). However, my Das Keyboard Professional arrived today in the mail and I replaced my Logitech keyboard with it. Upon trying to use my webcam, I discovered that it was no longer working. Upon reboot, I discovered that my Das keyboard was not working as well (even on the Windows 7 login screen). After unplugging the webcam, my keyboard worked properly. The reverse was also true, unplugging my keyboard allowed my webcam to function properly.
I have tried many different ways of plugging in my USB devices, including ports on both the front and back of the case and plugging the webcam into the USB ports on the keyboard. In all cases, Windows 7 will recognize exactly 1 of these devices. It appears to be chosen more or less at random if I boot up with both plugged in (without the webcam plugged into the keyboard). If I boot up with one device plugged in and then attempt to plug in the other, the second device will fail to install with Windows 7 giving a "USB device has malfunctioned" error. The device manager will list an Unknown Device as having an error code 43 (Windows has stopped this device because it has reported problems). If I boot up with the webcam already plugged into the keyboard, I will occasionally be able to access the webcam, although the image it produces is highly choppy and distorted (in a manner that renders the device worthless).
Additionally, I have tried uninstalling the USB root hubs and controllers and allowing Windows to re-install the drivers on the next login without success.
As I do not believe that excessive power draw is the issue, my suspicion is that there is some sort of conflict on some system resource between the webcam and my new keyboard which is causing this problem. Under the Device Manager, both the keyboard and the webcam have Address 00000004 (when the devices are operational), but I am not given the option to change the Address to try to resolve this problem.
I've done some digging around and the only suggestion that I've found that seems like it might work is to purchase a USB extension card. I would then plug one device into the root hub and the other into the extension card. As this suggestion requires a monetary investment and I'm not sure it would work, I would love to see if there are any ideas on how I can resolve this problem.
Thank you for your assistance!
Edited by MrVulcan, 14 August 2009 - 12:40 AM.