Update:
The Arduino Uno is fried. Connected a new Uno, and everything worked perfectly. Just a guess, but I believe the regulator may be off, hence why I was getting 2.6V on the 3.3V and 5V pins.
Update:
The Arduino Uno is fried. Connected a new Uno, and everything worked perfectly. Just a guess, but I believe the regulator may be off, hence why I was getting 2.6V on the 3.3V and 5V pins.