If I understand correctly, everything stops working, you connect a console cable and get no output from it.
Reboot it, and it starts working again, console connection works?
It is most likely hardware. Something forced the kernel to probably just stop working correctly.
You can check /var/log/messages and find what, if anything, was logged while the system stopped responding. And check /var/log/crash and /var/crash for core files that might be left. But if the disk is failing (usually the least reliable part), it might have stopped writing anything to disk.
Another option would be to leave a device connected to the console logging output from the 2200. Take care to make sure this device is adequately secured, especially if left logged into the console. Possibly run "dmesg -w" from the console (in expert mode), to catch any error output from the kernel that might not be saved any other way when it stops responding.
These messages are usually not that easy to understand, but usually errors from hardware failures, especially the disk, show up quickly in google searches and can help validate that the device is failing.