Sharon Codrington asks:

    Please enlighten this young QA person as to the difference between
    QA & Testing.  Am I right in thinking that QA is more a preventive
    thing, ensuring quality in the company and therefore the product
    rather than just testing the product for software bugs?

And Bret Pettichord answers:
    DING. DING. DING. You are correct.

    Most testing jobs I see are nevertheless advertised as "QA". Some people
    suggest that QC is a better set of initials to describe testing.

Don Mills writes:
    In my courses and my practice, I stick to the ANSI/IEEE
    definitions, which agree with what is generally held *outside* the
    software arena.  The definitions boil down to:
          *  TESTING means "quality control"
          *  QUALITY CONTROL measures the quality of a product
          *  QUALITY ASSURANCE measures the quality of processes used
             to create a quality product.

Rick Hower addresses this question at
<http://www.softwareqatest.com/qatfaq1.html>.