Lsgoodcare USB Audio Cassette Tape Converter to MP3 CD Player PC Simply put in the cassette tape, connect it to PC and use the supplied software to convert the whole tape into MP3 format 3.5mm earphone jack,Auto Reverse and Bi directional playback operation Powered by USB or 2 AA batteries (not included) Support Windows XP/Vista/7, Mac OS X (Mac operation requires download of free software). if you put the cd in your computer, it shows mistake. please download this free software""Audacity"" from this web: http://www.audacityteam.org/ after install the software ""Audacity"",put the usb cable to your computer, and this audio cassette tape converter will begain operating; if it doesn't operate, change the usb cable(anyone fit the converter) and try again.