Windows Media Player CD-R burning problem

I’ve been using Windows Media Player quite successfully to burn music CDs up to 78 or 79 minutes long until recently. Now when I want to burn a list of songs, WMP cuts off the songs at about 70 to 72 minutes, which started happening only yesterday. I’ve tried reinstalling WMP but the same problem occurs, and I can’t find anything in the help file to address this. Is there a way to fix this problem to burn up to 78 minutes again? Thanks very much. =PSH