Booting into bios after installing HDD

Posted by Plus_Wrongdoer_3249@reddit | buildapc | View on Reddit | 4 comments

so, I had an old 4tb hdd laying around, it was an external version. I was researching online that I could turn it into an internal version my removing the adapter, so I did. I turned off the PC, plugged it into the sata power adapter (on the same line as my ssd boot drive), and plugged into motherboard. when I tried to boot got a small burning smell, and it booted into bios. now neither drive is showing, only my mv2e drive. What happened and what can I do to remedy the situation?