Notebook Boot and Lockup

The problem started after I replaced the battery (then also had to replace power button chip  because it was literally broken) - the laptop won't start up, even when plugged in.  When pressed, the power button, after about 3-4 seconds, will briefly light up with a blue light, then nothing.  The light where the power cord is plugged in is lit, so even if the battery isn't working it should boot.

I went through the HP automated assitant, as well a a few posts in the community and elsewhere, and I have a feeling something is wrong with the motherboard or BIOS.  I did the thing where you hold Windows+B while pressing power, even downloaded a BIOS update onto a flash drive and did it...nothing.  One rabbit hole I went down suggested I remove the CMOS battery but I can't seem to find it (and some things I also suggests that this laptop doesn't have one -didn't know that was even possible?).  

I know the single blue flash on the powerbutton must mean something specific, but I cannot find an answer to what that is!  Any help would be appreciated.