First of all, stop using strong shampoos that could harm the tender skin of your scalp. Wash your hair regularly, keep it clean but don't go to any extremes - twice a week should be enough, unless you work in a somewhat too dirty environment. Otherwise you deprive your scalp of some rather important substances your body creates and supplies for your hair.
Dissolve one table spoon of salt into 250 grams of lukewarm water. Wash your hair with your shampoo and then pour upon it the prepared solution. Let it be absorbed by the skin of your scalp while you wash the rest of your body during that time. When finished, wash away the salty water from your head. Carry out this procedure for a month or so.
If this method doesn't show to work at all and you can't see the difference before the end of the third week, the problem you are dealing with might be connected with those skin micro-organismsis so called Malassezia yeast species. Don't get upset but spend a few more dimes on some cotton-wool and a phial of weak 2% solution of Spiritus Salicylic at your nearby pharmacist. Take a small stick and a little of the cotton-wool. Make a swab. Soak the swab into the phial of spirits. Gently rub in the solution - just a little bit everywhere on your scalp. Carry out this procedure once a day for three days in a row and on the fourth wash your hair.
In case that treatment doesn't help you either, the reasons for the scurf could be from the kind of water in your area to what some detailed tests in a laboratory would determine...