Hi everyone! I am having real problems trying to understand when to use почему and when to use зачем. I have tried asking Russian friends of mine, and get a similar response each time, 'I don't know....you just have to know when to use it' - which is not much help when you are trying to learn a new language! I was just wondering if any of you have any tips or rules you know of which could help me know when to use which 'why'. Thanks to anyone in advance!