downshifter

Hi! I'm having basically the same problem. When I try to cut a number of mp3 files together to one long mixed file (by opening the first file, copying this into Windows clipboard, opening the second mp3 file, moving to the end and pasting the first file from Windows clipboard) only the first mp3 file is in original sound quality and you are able to listen to it. All following inserted files are in very poor sound quality without any dynamic and it cause pain to listen to it. Who can help me to solve this problem? What is it I'm doing wrong? Thanks in advance! Regards, Andreas (Germany)