If all of the garage outlets are "daisy chained" and you have a wire burned off in the first of the chain that would explain it. Next in the US all garage outlets should be on a GFCI and if a GFCI fails all of the "load" outlets tied to it will quit working, I have seen that before.
Finally depending on how many you have I would remove the face plates and remove the outlets one by one inspecting each one. Since you have tried resetting all the breakers as mentioned I would start looking downstream of the breakers. I would also check the downstream side of the breaker labeled for the garage. I assume you have a meter?
Ron