Hi 2rko, what aspects of case studies do you have problems with? Or is it the term itself?
Really, a case study is a general methodolgy to gather both primary and secondary information about your topic. It is 'general' because in order to create a good case studies, you need to combine a number of suitable methodolgies, such as interviews, questionnaires and a number of secondary research, to obtain information that you need.
So a case studies in not a single methodology, but a multiple of different methodolgies that in effect, act as one that gather the best possible information for that particular person, or group.
I hope this clarify the fundamental approach to what a case studies requires.