I will try my best to help you, flash back to shipped ROM and once you have loaded the shipped ROM, do any update PRL update if you want :P no need to do so and assuming you have unlocked you device, download a 6.5 ROM for cdma diamond... not tp or gsm, and flash over to it!
EDIT: forgot to say in order to be able to flash to another ROM take out the battery and put it back in and hold the power button and volume down button! it should successfully go into boot loader mode.