I know this seems like a lost cause, but the last two days I've tried multiple things with this motherboard to try to get it to work. As usual, when the PSU is plugged in, it will turn on without me pressing the power button. It will, however, turn off if I press and hold the power button in (I have a little one that is independent of a case). It will also turn back on when I push the button again. All three keyboard indicators will light up when it first powers on, and the monitor acts as if a signal is being sent to it for a split second, and then everything goes "dead." So power is getting to it, and I think the video card just starts to display something, but then it gives up.
I have tried three different CPUs, and have tried powering it up in both the diagnostic mode and normal mode, defined by a little blue jumper on the motherboard. When the jumper is set to diagnostic mode, it does the same exact thing as it does in normal mode. I tried a Celeron 333MHz/66MHz FSB, a Coppermine Pentium III 600E, and a Katmai Pentium III 500MHz/100MHz FSB. All three processors will heat up, as if they are doing something. What that could be is something I don't know. I have tried removing RAM, and it provides no beeps. Normally, this would indicate a dead motherboard, but it did this same exact thing back when I first caused it by installing the IDE connector backwards. It will not do this when the floppy drive connector is done backwards; only the HDD connector, which goes to the primary IDE port on the motherboard. It has POSTed plenty of times with the FDD cable hooked up backwards, and I turned it off and fixed it and it ran just fine.
I'm doing something wrong here, and I don't know what it is. Visually, the motherboard looks just as good as when I first pulled it out of the box- I don't see any way that it could've gotten damaged in a visible, physical manner. This only happened when I connected the Quantum Bigfoot TX drive into it- I was trying to see the size of the HDD seeing as it would spin up normally when connected to a standalone PSU. What that has to do with anything is something I also don't know.
I'm trying to fix this motherboard so aggressively because I don't think I'll have the money to buy another Slot 1 motherboard like this for a long time, and because of the fact that these SE440BX-2's now run for upwards of USD$200 on eBay, and run for a minimum of USD$100. Back when I bought it, I only paid USD$40 for it. I'd have to go through another good set of research on whatever motherboards are available on there, that is if I even had the money for one of those in the first place.