OK I had this very problem. Was almost hopeless and was ready to trash my Diamond. After a long deep breath, I found the "official" ROM for my device, Telus HTC Diamond, not a rebake which another poster suggest as well you avoid then flashed my device with the official stock rom. Did a hard reset and let the phone connect and do it's thing. Seems the phone does all kinds of stuff to go live on your carrier network... Anyway, I then reflashed with the ROM of my choice and so far has been OK touch wood. I tried everything, hard resets, battery out... Oh one step I did do is relock since I was going to take it in for service/replace. So perhaps not perfect process, this did work for me. My only advice my fellow bleed-edge rom users, take you time and you will get yourself back to the ROM of your choice.
