airplane mode and caps lock led flash, runs for 1 second then dies

I plugged in a new external hard drive to back up my data. Now, when I try and start it, the side power led and the airplane mode and caps lock lights flash, the fan turns on for 1 second, then everything dies. Have tried several hard resets, disconnected the battery, etc…. still doing the same thing. Any suggestions? If I need to boot from a usb, where do I get the boot software?