Hi....If you masturbate daily that is not really a problem.Some people masturbate 2 or 3 times a day , but then they miss a day as well.Everyone is different on how they release there tension.You seem to have the problem of masturbating just for the sake of doing it.
It appears that you have got yourself into the habit of masturbating because your that use to doing it ,that its an easy excuse to get your mind off other things you need to be doing.You say you need to study but as you cannot get focused on it , you turn your mind to other thoughts.
In regards to masturbating you most likely will not beable to go cold turkey and completely stop.Your better to just cut down on how many times a day you do it.For example you may do it once in the morning before you get up then dont do it again before you go to sleep that night.Try and hold out though the middle of the day and start doing your studing and other things you need to get done.So far you have been trying as you say you deleted all your porn and trashed your DVD collection.What you need to do now is keep your mind off sex and stop thinking about masturbating.Its tuff to start with but as each day passes you should beable to cut down on this habit and do other things you need to do.
Good luck and im sure you can beat this problem with your will power......