Does it even power on?
Make sure your ROL board is connected and the xbox has an A/V lead plugged in and try turning it on. If it powers up and gives you the 2RROD/1RROD, then that's a good sign at least. If it's not even doing that, you buggered something up.
However, I would highly recommend you go and get a proper reflow done, with actual rework equipment instead of a heat gun. Heatgunning chips can kill them, and overheating your XBox on purpose can blow capacitors. If you're still intent on doing it, then don't forget you probably need to block off as much airflow as possible.