MY xbox is a mod and I started deleting somthing that I didn't wanted deleted so I turned it off while it was erasing. Now when I turn it on it comes on for 3 seconds and go off then it comes back on and flashes green to red and never comes on just keeps flashing.
What did you delete? Maybe it's coincident but that behavior sounds like a bad power supply. Does your box not come on sometimes when you press the power button? You said it's a modded box (chipped or softmod)?