From the Xbox Support pages:
Flashing orange, solid red, or no light: Your power supply may need to be replaced. Try the following solutions:
Plug your console’s power supply into a different electrical outlet. Do not use a surge protector.
If the power supply light is solid red or flashing orange, unplug the power supply and let it cool for 30 minutes. Then, plug the power
supply back into the outlet.
If your power supply light is still flashing orange, solid red, or
unlit, your power supply needs to be replaced.
Its possible that your power supply is no longer functioning correctly. If the power supply wasn't working properly, it is also possible that it could have fried something in the Xbox, since fluctuating or abnormal power levels have the chance of doing that.
As for the red ring of death, there are numerous things that it could be. If you are getting the infamous three red lights, its considered a "General Hardware Failure." No error code should pop up on the screen if this is the case. You said you attempted to get a code, but could not get the unit to power. If this is the case, you may be experiencing one red light, which is considered a "Hardware Failure." A code should display on the screen if this is the case. For two lights, it means the console is overheating. It should turn off, and the fans will continue to run while the unit cools. If you have four lights, check your AV connection (if connected this way). You shouldn't see this error with an HDMI connection.
In any event that there is a hardware failure, its likely the console cannot be saved unless sent for a repair.