Green Light comes on but doesn't Boot

[MrE]

Ok, so The DS lite MB will power up and even stay on BUT doesn't boot and the screens don't light up or flicker.  It is not a screen issue or a BIOS chip issue as both have been tested on another MB and worked 100%.  One thing I'd like to note is that I noticed even with everything disconnected from the MB, I can turn it on and it will stay on - UNLIKE how it should turn right back off after realizing screens are disconnected, etc.

Any ideas on what the issue might be and if it can be fixed?

[rocky]

I have a few motherboards like this as well but I have not yet figured them out.  I know its not the battery, screens, fuses, bios, power switch, or anything like that.  It has to be a chip on the motherboard somewhere.  Sometimes I have had pieces that fall off that cause that problem but I don't see any on mine.