First, get rid of the CD drive. Even if the system was working perfectly, the drive wouldn't do anything. It's not bootable, and right now it's just additional clutter on your IDE bus introducing another variable into your problems.
Pay very close attention to the power LED. It has two brightness levels. It starts dim, and if everything checks out, it should jump to the brighter setting and start the boot process. It should also be accompanied by a little flickery jump on the monitor.
If the power LED never jumps to the brighter setting, that often suggests a loose connection between the CPU card and the motherboard - even if it looks rock solid. Double check it, then triple check it.
(And that board on the back of the floppy drive isn't to correct for a bad cable. It's a dedicated circuit, originally sold with that very drive as a complete high-density floppy package.)
Others here have reported floppy cables as responsible for dead-like symptoms, so try replacing it or omitting it. The latter will introduce a natural delay in booting, so be patient if things still look the same.
There is also the possibility that the machine just simply died before it got to you. I have a 4000 here that was working beautifully one day and was completely toasted the next due to capacitor damage (which I should have seen coming - no battery damage, though!).
Here's a
direct link to the auction for others to check the photos.
