My world is much better now, not to mention my friend's world since it was his Xbox.
The solution:
After trying everything that was suggested in this thread, and your help is much appreciated, I removed the pinheader from the motherboard. Upon removing the pinheader I deiscovered that three traces were no making contact with the LPC. I decided that they were proabably damaged during one of the times that chip was removed prior to this incident.
Anyway, with the pinheader gone I could see the non-working traces and repaired them. The traces came very close to the LPC before making contact, so instead of reinstalling the pinheader, I did a direct-solder with the chip. I know that this is not recommended but it was my only option.
The Xbox works, I successfully completed another repair, and my friend has his Xbox back. What a way to end the week.
Once again, thanks everybody for your help in this matter. I'll stay around the scene for a good long time because of the support that you can find here.
Megahurt
