Won't boot, "authentication failure", UUI

[JLinks]

Hi, I'm kinda new to Linux, but it seems like I know what I'm doing.

The other day I installed Mint 10 (the main one) on a 2gb USB stick using pendrivelinux.com's Universal USB Installer, with about 500mb of persistent storage. It was working fine until earlier today. Now when it tries to boot, the Mint loading screen appears for a while, then just goes to a black screen and prints "Authentication failure" several times. I've tried it on 3 machines, and, actually, only one of them says authentication failure, while the others just sit at the same screen without that phrase. I can't type anything in, but if I press the power button it shutdown normally.

The problem started when at first it went to the log in screen. Which it hadn't been doing before, since it's a live usb and I never entered a user account password or anything. "Automatic login" was selected, and pressing the button to login wasn't doing anything. "Other..." was the only other option, which led to asking for a password, with which I had nothing to put in. So I clicked restart, and the next time it booted, it just stayed at the Mint loading screen. It booted like this 3 times or so, then, without me doing anything differently, it started doing what I described above.

The only thing I could have done that I can think of is that I had set the master password key thing while connecting to my wifi network. After entering in the wifi password, it then asked for a master password or something, which I at first left blank, but it then said leaving it blank wasn't recommended, and wouldn't stop popping up every time I connected, so I figured I'd enter something in. It was on the next boot that the problem started.

Please tell me there's a magic button somewhere I can press to make it start working again. I could just reformat the drive again and start over, there's only a few files I'd lose, but I really don't want to go through that and customizing Mint so much again. Is there some way to recover files from the persistent storage and/or Mint's customizations?

The laptop on which this started and it says authentication failure is a Dell Vostro 3700, which happens to not be booting from its windows installation.
The other computers I tried it on were a Dell Inspiron 1525 (which happens to have hard drive problems) and some custom built desktop which is in good working condition.

[dawgdoc]

Is it possible to boot to a computers installed linux OS, plug in your USB drive and save your persistent files, specifically your configuration files?

To solve the issue without reinstalling may be a matter of removing the keyring files. This is not something I have done, but it sounds like that based on threads I have read. This may be a thread to start with http://forums.linuxmint.com/viewtopic.p ... te#p330294

Read carefully about the keyring before deleting anything. And this still involves being able to access the files in your home directory. I hope that helps a bit.

[JLinks]

Thanks for the help! I figured out how to mount the casper-rw file on another computer and retrieve some of my files, though some of them were missing, curiously. Nothing important. I also tried removing the keyring files as you suggested, which at first it wouldn't let me, but I did in the terminal. The stick still won't boot, though. I guess the problem is unrelated to the keyring, as I would've thought, but I can't think of anything else unusual I did before the reboot. Any other suggestions, or any explanation why this might've happened? Well, I guess there's no point in spending any more time on fixing it rather than reinstalling now, so thanks anyways.