Don't know of any reset, there is a main fuse. Don't know why leaving it on would blow that. Check your cable connections, grounds and fuses. Maybe unrelated problem.
12.25 (12.7 Normal.) is a little low but you should hear or see something. Does your headlight come on? What does the battery read with the key on? It should drop a little if not maybe the main fuse. Some of your fuses are behind the panel on the left, maybe the main fuse might be under the seat.
Do you think the battery could have been so low that it also pulled the test battery down? Be sure both battries are charged, maybe try again.