Try this: Power-cycle the screen right after booting
I'm aware screens might lose sync, I've tried
How do you know it doesn't boot if the screen is off?
Because the screen goes off after loading the kernel with the "rotating star" thingie.
If you leave it 5 minutes or so, and try and ssh in does that work?
As I've written in the original question, I couldn't log in for at least 15 days (remotely), but locally neither.
Along the same lines: Watch the ethernet light and the disk light
The ethernet light is orange. I think it should be green.
What's the last text you see on the screen before it goes black?
Can't really see what it says, but i think it's the second stage boot loader that starts with a "rotating asterisk" thingie.
You can test this. Boot into "single user mode" in the beastie menu
I unfortunately disabled the beastie menu. I tried interrupting the second stage loader, but can't.
Maybe a cron
job did something to your system, e.g. some update.
I had a lot of SSH bot logins, that's for sure. I used
ipf for a long time, and was just about to switch to
pf.
What's the last text you see on the screen before it goes black?
I can see BIOS POST, I can enter BIOS setup, etc. I can even see the mbr loader (bootcfg), and the boot0 loader.
I can interrupt the boot0 loader. But after that, no dice.
I also once managed to get the FreeBSD logo to show, by pressing a lot of keys after boot0 finds the partition.
Still no boot.
I even reset the battery on the motherboard, because while power cycling the machine (for some reason, I don't where is the reboot button, it only appears to have one),
I got some nasty warning about POST failures, with several things mentioned like memory, keyboard and USB. I guess I confused it with force shutting down.
Thanks for the replies. I'm going to try a rescue USB.