Hi, all. This is my first post here. I'll start off by saying thanks to everyone here. I've spent a lot of time here getting my MacPro1,1 working with El Capitan.
That being said, I've run into a bit of a problem. It's been working mostly fine for the last few days, up until this morning that is. I woke up and woke it up like I normally do, checked my email, yotta yotta, went to eat and when I got back, it was showing a black screen with the white apple and nothing else. I figured it had just kernel panicked while I was away and was unsuccessfully booting to the Leopard installation (I somehow broke my Leopard installation while installing El Capitan and was planning on going back to fix it later) so I held the power button until it turned off and then pressed it again to restart, but now, nothing. It won't do much of anything.
When I press the button it seems to turn on, the power light turns on, the fans all turn on, but that's it. It won't output any video, it won't make any sounds, it won't do anything.
So far, I've tried:
rebooting it, many many times
unplugging everything that didn't need to be plugged in
pulling out all but one hdd to try to force it to boot off of that (I tried with both the El Capitan drive and the older Leopard Drive)
pulling out all but the original two 512 MB sticks of memory
pulling out the USB 3.0 card
pulling out the ATI graphics card and putting the original NVIDIA card back in
swapping the port the monitor is plugged into
using a different monitor
booting from a leopard install disk
booting from an El Capitan flash drive
booting from an apple firmware reset disk (or whatever it's called)
resetting the SMC
resetting the NVRAM
booting it without anything connected including keyboard, mouse, and monitor
booting it without the memory risers installed
leaving it unplugged for a long time
leaving it on (in it's zombie-esque state) for a long time
booting it in safe mode
booting it in target disk mode
I've tried everything I could think of and nothing seems to be working or doing anything whatsoever. It didn't even make a sound when I tried turning it on without the memory risers (which it should have). I can't get it to play the boot chime or anything.
Also, none of my keyboards seem to do anything, no matter where they're plugged in. The caps lock keys won't light up at all. Laser mice will light up, but only if they're plugged directly into one of the original USB ports on the Mac Pro, they won't light up if they're plugged into one of the keyboard hubs. I can't even get it to eject the optical drive tray by holding down the mouse button.
I'm sort of wondering if this is a logic board failure, but if so, it doesn't make sense why, because it did successfully reboot (into something) the first time, it wasn't until I manually power cycled it that it started being completely dead.
One last thing; for a while now it's been saying I only have 11 GB of memory installed when I actually have 13 GB (6 x 2 GB sticks and 2 x 512 MB sticks). I tried running diagnostics and memtest on it at the time, but memtest only showed problems when I was using a very old version of the software, the new version passed it with no problems. I rearranged the sticks at the time, and it temporarily went back to listing 13 GB, but shortly thereafter it went back to only listing 11 GB. I'm not sure if this is related or not.
Thanks for any help you can provide, and I'm crossing my fingers that she's not dead because I'll probably cry if so.
EDIT:
For some reason I decided to try pulling out the CMOS battery, long story short, she's alive. I have absolutely no idea what happened so if any of you have any ideas, please let me know. Also, the LED is on for DIMM slot 3 on riser board one, which I'm assuming means that stick is bad. I'm going to RMA it and hopefully this never happens again.