No more wood

Can a small tight rubberband wrapped around the base of the penis twice for 40 minutes cause ED?
On Sept. 1 2005 I was trying a technique called "Jelqing". At the time I was 24 I remember when I  took off the rubberband,
there was in indention line at the base of my penis.  I'm black and my penis was cold and purple.  I immediately called
the urologist and made an appointment a weak later.  They didn't say anything was wrong.  The doctor said the penis is basically indestructable.   I saw two more doctors over the next 6 months.  All they did was give me viagra. It worked sometime, but the when the woman gets on top it goes soft.I saw another urologist who actually ran a test, he did an ultra sound, and a digital rectum exam and said the ultrasound looked ok and that he thought I had prostatits. He said my prostate was imflammed. I took antibiotics which helped me start to get morning wood again, HOWEVER after a few days the weak erection problems returned.  I'm pretty sure I ruptured or damaged a blood vessel.  Since the rubberband incident I've had a new vein my penis that is always there "soft or hard". The vein runs across my penis near the base. I've probaly only had morning erections maybe 20 times since 9/1/05.  My penis does not get fully hard it feels deflated along the undercarriage.  
I'm not diabetic, no high blood pressure, no high cholesterol, no meds, but an stressed out by this problems and bad sexual relationships since this problem.  What do you think is the problem for my weak erections?

[SixStringer]

While I am not a doctor, I do not agree with the one doctor that " . . . said the penis is basically indestructable".  There are many things one can do on purpose or by accident that are detrimental to the male sex organ, some of which can be found in the forums on this site.  I sympathize with your concern, and I do not believe that you have been given the right answers as yet.  I think your troubles are mostly due to the rubber band incidents of the past, but now you need someone to help you correct those problems, and that involves finding the right urologist.