what is the difference between μην/ μη and δεν/ δε can you please give some examples ?
what is the difference between μην/ μη and δεν/ δε can you please give some examples ?
μην/μη is like for active actions. it's for giving prohibitions, requests, or suggestions. 
μην ανησυχείς. 
μην πας εκεί. 
μην εισέρχεστε, ιδιωτικός χώρος. 
μη φωνάζεις. 

δεν/δε is passive and about something that you don't have or haven't done. it's like a fact. 
δεν έχω πρόβλημα. 
δεν έχω σχολείο σήμερα. 
δεν έχω ταξιδέψει ποτέ με αεροπλάνο. 
δεν έχω αλεύρι για να φτιάξω κέικ. 
δε φωνάζω. 
δε μου αρέσει το παγωτό. 

@timonrosso the simple rule is that δεν and μην maintain the final ν when the following word starts from vowel or from one of the consonants κ, π, τ, μπ, ντ, γκ and double ξ, ψ. of course, there are some grammatical exceptions but i can't recall them all. if you feel confident reading greek, you could try this here http://3lyk-ioann.ioa.sch.gr/pub/balatsos.pdf
it explains extensively the rules for the final v in all cases 