Originally Posted by theducks
Calibre version is 0.8.3 Not that thing
in the repository.
Repeated crashes on start (no device connected) might indicate bad hardware.
I would suggest running Memtest 86+ from the (GRUB) Boot menu (or Live CD) for 1 or mor PASSes (many tests in a PASS)
Calibre can be heavy on the Memory use.
Lint in fans and fins is another common issue.
Version is 0.8.3.
The rest I would need a few days to understand