I have Dell optiplex260, with windows xp. I have problem every time I connect usb flash memory or cd writer or any usb device, I get this message ” USB device is not recognized…” and it disappears quickely, but the device it works properly with noproblems except this message every time I tried to access my usb device. I checked usb driver and reinstall it again from device manager and no problems appear. I even reinstalled all the system driver. but no use, same problem presist. please I need ur suggestion about the annoying problem.