Notebook won't boot after BIOS Rollback, WiFi key blinks orange

Hello,

My HP 250 G2 F0Z26EA#BH5 Notebook won't boot. It has the WiFi key blinking orange light at 2 sec interval and not booting and won't power off even when pressing and holding power key. It all happened after a Bios Rollback (wanted to move back to the original Bios) The HP Tech team couldn't help solve the problem. They say it's a motherboard problem that I'll have to change my motherboard. I know that changing a motherboard costs a fortune, it's like changing a system and I cannot afford the cost. Another thing is that I have a BIOS Encryption, I added a Bios password to the System both Administrator and Power-on Password. The troubleshooting steps like removing all power source, then pressing and holding power key for 15-20secs and after plug Power cord without battery didn't work. I've also tried holding Windows key + B and then Power on. The System didn't boot but they WiFi key light remained steady. Now the last Agent that called asked me to keep pressing F8 key or Shift+F8 key immediately I pressed the Power button. I am yet to try this but I forgot to tell her that I have a BIOS Encryption (well she asked me but I wasn't sure what she was talking about so I said No).
I cannot afford to change the motherboard (even though they haven't given me a quote yet). I planning on selling the System for a new one before this.
Please help me get the Notebook operational. I need to get back to work with it.