My toshiba wont start back up after I shut it down. I tried taking out battery, holding down power, also tried to access the hidden recovery by holding 0 and powering on. Nothing is working. Now it says check cable connection and to reboot and select proper boot device or insert boot media in selected boot device. How do I know if its a hardware problem? I can get to f2 and f12 but nothing works and this computer is only 5 months old. Any help would be great! Thanks!