WHY is my menstrual blood brown & pasty?

I really want to know why the blood is brown and pasty. What is the cause? How can I get it to change back to red? I am 22 and was diagnosed with PCOS in Feb '06. I hadn't had a cycle from AUG '05 to March'06. I then started taking ortho-novum but the blood since then has been pasty, brown, and chunky. I am not stressed, not pregnant, I could definitely improve my diet, but I just want to know what this condition is, how it can be treated or what I need to do to better take care of my body so my flow will flow normal red blood.

I am 19 close to turning twenty, never been sexually active, and not on any type of contraceptive. I have a healthy diet, as healthy as I can when in college that is. I recently have been having all brown or black blood that's pasty during my cycle as well. I have a doctors appointment soon, so when I get tests results back I will have more info...hopefully....on this.

I am going through this now and for two months in a row it has been this way. If you can remember aura9969, what did the DR. say at your appointment in 07?