My Raspbmc-based media centre has been running happily for a couple of months, undisturbed. It's not on constantly; I don't have enough power sockets for the TV, stereo, RPi and games consoles, so I swap things around. It's usually just on for a few hours most evenings. I always shut it down properly from the menu, and make sure it goes completely dead before unplugging the power.
A couple of days ago, it froze completely; there was no response using the IR remote or the USB keyboard. I tried to ssh in, but it wouldn't accept the connection. I left it for a few minutes, but was forced to conclude that it was totally stuck, and pulled the power.
Since then, I've been unable to boot it. I tried a fresh Raspbmc install on a clean SD card, but the behaviour was exactly the same. I noticed that the power supply on the USB hub I'm using was whistling slightly in the way that can mean a problematic connection, so I unplugged all of the peripherals except the IR receiver (which is very low-power) and powered the RPi directly from a 5V 1A smartphone charger (which I've used successfully in the past), but this made no difference.
The error I get is as follows:
init: udev pre-start process (41) terminated with status 127
I've searched for this, but I get a lot of results that refer to other processes, other Linux builds, other hardware... I'm not particularly experienced with Linux, so I'm not 100% sure what's relevant and what's not, but so far I haven't found anything that looks like it'd help me.
Can anyone suggest something I might have missed? A clean OS install, a stripped-down setup, a known good power supply... I'm not sure what else to try.