Lenovo T530 Laptop with Windows 7 restarts perfectly if only on battery or if only on AC adapter (with battery removed). When both battery and AC adapter connected then laptop goes completely dark during a restart except for a fan I can hear. When this happens I can still force a shutdown by holding power button down for 5 seconds. Battery seems to be fine and will charge to 100%. Anyone have a clue to what can cause such strange behavior?