Toshiba X505 new MB question

I'm working on a Toshiba Qosimo X505-Q830 that would not boot or go into POST. I bought a new in the box MB for it and fried that one by plugging in the power supply to the wrong connector (there are two identical connectors, one for 90W power and the other for 120W).

I bought another new MB and also a used tested i7-740QM CPU. Ram is new DDR3-1333. Power supply is putting out 19V. All the laptop does now is flash the power LED. I have an X500 manual, and it does not describe this LED as a diagnostic tool, only the DC in LED, which is properly lit. When I pull the CMOS battery and then put it back in, the fans spin for a couple of seconds and then the power LED flashes. I've tried the hold down the power button for 30 seconds with various times removed and it makes no difference. I loaded a new Toshiba BIOS on a USB drive and could get the drive's LED to flash briefly by holding down the Windows+B keys, plugging in DC power, and pressing the power button. It then goes back to the power LED flashing.

Do new Toshiba MBs have a BIOS on them? It seems to me the BIOS is absent or damaged. I'd like to find a way to flash it if possible. Thanks for any help.