I still got this dandruff problem !!!
Introduce Yourself
What do your flakes look like? If they're small, white and loose with no odor then the the type of dandruff you have may be pityriasis capitis and is cause by the dead skin on the scalp shedding quicker then you can wash it away. This type of dandruff is commonly treated with over the counter dandruff shampoos* and regular acidic rinses like apple cider vinegar.
If your flakes are thick, greasy and yellow or off white then it may be seborrhea dermatitis which is caused by heavy product build up, especially if there is a musty smell in th hair that lingers even after washing. Using a clarifying rinse and staying away from heavy products is the best way to treat the scalp.
If you have been using some sort of medicated shampoo or rinse in your hair for more then 3 weeks without any result, you should really go to a dermatologist so they can see if you really do have dandruff or some other skin condition like psoriasis which is commonly mistaken for dandruff and has be treated with a prescription.
*Be careful with the dandruff shampoos, many of them will dry out your locks. Any of the rinses mentioned in the other responses would be good alternatives.