Bricked? Evo 4G while trying to Unroot I am an idiot, first and foremost.
I was running an older version of CM7 and just bought an Evo 3D. I decided to sell my Evo 4G online, and went to unroot it. I ran the original software RUU (1.06.651.4) on the phone, (because I am dumb and didn't think things through) and now it is semi-bricked.
Symptoms:
The phone turns on with only a black screen (it is "lit up" but nothing appears on the screen). The phone vibrates once, then the phone plays a sound (a little tune) to indicate it is booting up.
The phone plays a sound to indicate a low battery warning. The phone plays a sound to indicate when I connect the USB cable to it.
If I try to boot to bootloader by holding Vol-Down when powering up, the black screen appears with no sound and no further action.
If I try to re-run the RUU, or run a different RUU, I get a USB Connection Error.
I can't run an RUU, I can't flash anything because I have no access to Recovery, etc.
Can anyone help fix my stupidity? I shouldn't have rushed into unrooting. Damnit.
Happened to me one on my DHD 
my phone had same symptoms
what i did was take the batttery out then Hold the power button and then insert the battery into the phone again (while holding the power button down/ pushing) and my phone rebooted into bootloader and from there i switched to recovery
hope this trick will work for you.
good luck