Private Key suddenly not on keyring?
I've only been using PGP Desktop a few weeks. I had created my public key and provided it for someone to use to send me files. This worked well for a few transmissions, and then all of a sudden when I went to decrypt a file today I got an error message that there was no usable private key corresponding with my public key (which had been used to encrypt the file). I haven't deleted anything, this is the same PC I've been using, etc., so I'm confused about why it would suddenly be gone.
I did not have a backup of the private key, so I gather than I am out of luck in recreating it, right? I'll have to generate a new pair to use?
Without knowing what happened, I'm worried my private key will disappear again. Can you point me toward best-practice documentation about creating and restoring from a backup?