Hmmm - you provided no description of which hardware you're on, which os, no log files, no description other than "it crashed", so you're not going to get a lot of help with that kind of skeletal problem description....and this is a weewx forum anyway, not a "how do I fix my broken computer" forum, so you won't find a detailed howto here regardless.
That said, typically you want to run "fsck" against the drive after inserting it into a working linux computer of any kind, and cross your fingers that you might get lucky and restore some files off of the disk.
A couple links that might help:
FWIW - I googled for "fsck usb stick linux" - try that and see if any hits make sense to you.
(but when you restore/recover/reinstall things, please do a backup of your setup for the next time)