Songs from cd on itunes not playing unless in a playlist???

Songs I have downloaded from my cds used to play once selected from the 'song's list. Now they only play if they are in a playlist. I have thousands of songs and like to choose randomly without creating playlists. Why won't they play when they used to? I'm currently using Windows 10 but was getting a Macbook for my birthday. Reluctant to switch if I can't access songs as and when.