Although this can be a coincidence, electronic equipment will always generally last longer if kept powered up, (even when in standby) its the action of an electronic component cooling down then being reactivated that can trigger a fault in any "iffy" component, I suspect that this is whats happened in your case. Any DVD equipment showing "loading" continually indicates that the laser is not able to read the disc properly, try resetting the logic circuitry by disconnecting the unit from the mains for a few minutes, re-connect and try it out again. (also try another disc)