I have installed VirtualBox under windows 8 operating system to use Windows XP. Everything seems great but i can't use any devices through USB port in virtualbox. I have enabled the VirtualBox Extension Pack 4.2.4, but nothing happens. I am using the latest version, downloaded today! So, why any USB ports are not working in windows XP under VirtualBox?
You need to enable the USB Controller first. You can find it under Settings > USB.
Also, make sure you install the Guest Additions too, they are required for USB to work, if I am not mistaken.