Yeah that is very bizarre. After you flash and reconnect it to you pc, can you go to device manager and just see what driver is loaded as maybe the FC is stuck in bootloader mode?
Otherwise last thing is to try on another PC if you have access to one to double check but I am fairly certain that is bootloader issue if you can flash always, but never connect. If this is the case the just send support and email with your order number and ki k to this thread and we can get it fixed for you.
Also might be worth double checking the boot pins are not shorted somehow?