Irritated, Dry Scalp Problem?

I have a very bad scalp problem. Its dry, it itches a lot. When I scratch my scalp flakes fly out like it's a blizzard. This even happens when I wash my hair with selsun blue. Which doesn't work. Plus, my hair smells awful. Smells kind of like puke. I've tried every thing to hair grease to selsun blue. When I examine my scalp I have these raised harden flakes or scabs. When I pick at them, they bleed a lot. What can stop all of these symptoms? What products? Anything that stop this predicament.