Use something Acronis True Image. BUT if you are using CDs it may take an awful lot of them.
Most people have their system set up as a single drive partition (i.e. C: ), as supplied by the vendor. So a backup would have to contain all of this.
Much better is to create separate smaller and more manageable partitions. E.g.
C: - Operating System, Programs etc. Back this up periodically (e.g. before Windows monthly updates downloaded).
D: - Volatile Data (i.e. what you work on all the time, such as documents, emails etc. and should be backed up daily).
E: - Stable Data (things that don't change much, such as music, photos and may be backed up periodically).