I have a WD My Passport Ultra USB external drive which will not work with my Windows 7 laptop. When I plugged it in to the USB port it failed to install a driver and then it did not appear under My Computer. The failure message was: "Device driver software was not successfully installed". According to the manufacturer's website it does not require its own driver but uses a standard driver built in to the operating system. The drive shows up under Control Panel -> Hardware and Sound -> Devices and Printers -> Devices, with a yellow warning triangle. It also shows up in Device Manager under Universal Serial Bus controllers, also with a yellow warning triangle. Looking at its properties here, the device status is: "The drivers for this device are not installed. (Code 28). Access is denied. To find a driver for this device, click Update Driver". It does not show up at all in Disk Management. The external drive works on other laptops running Windows 8 and Windows XP, so I know that the drive works. A different USB external drive works on my laptop, so I know that there is nothing inherently wrong with the laptop or its USB ports. I have tried updating the driver, uninstalling the driver and following a few suggested solutions from this forum and others, but nothing has worked so far. Does anyone have any ideas? If any further information would be useful to you please ask.