Were you using Nero Express or Nero Burning ROM?
Nero Express is easier if you don't have to do anything particularly advanced with the creation of the CD.
To copy a CD (assuming Nero 7), open Nero Express, select "Image, Project, Copy" from the left pane and "Copy Entire CD" from the right pane. Then you select your source drive and destination drive from the top of the dialog box -- select your writing speed, number of copies, whether or not you want to "quick copy" and "verify data on disc after burning" from the bottom of the dialog box -- and then click the "copy" button in the lower left hand corner.
To burn an audio CD by using audio files from your hard drive, open Nero Express, select "Music" from the left pane and "Audio CD" from the right pane. Then either click the "Add" button to bring up a file browser or drag and drop your music files into the window. When you have all the files in there that you want and/or will fit, click "Next". Then select your "current recorder" which will be "Image Recorder" if you want to make a .NRG image file, or your CD burner if you want to burn to a CD, and then click "Burn".