To access your data, right click the hda# partition icons on the desktop and choose "mount". Right-clicking again and choosing "actions > change read/write mode" would allow you to write data to them if they are not formatted NTFS. As for getting your usb hard drive recognized and available, someone else will have to chime in there. I have no experience with exernal hdd's other than usb sticks which knoppix auto-recognizes.