The MSN, I think (it might be the other number that support tools asks for - you only need one or the other), you can retrieve from under the battery.
Write it down somewhere, then put the phone back together and get it into download mode.
Load up support tools, and put it in recover phone mode.
When that popup comes up, set the model number to the correct one, and type in the MSN, and click check. Now keep your fingers crossed, knock on wood, prayer helps, lol, whatever.. Just hope it takes.. Try a couple times if you have to, but remember, when you go to boot up the phone after, don't freak. Give it about 20 minutes on the logo screen, and it should come up.
Give that a shot and let me know what happens.
Peace,
~WickiD~