I have been using ubuntu for years, but I am ICT challenged. 12.04LTS recently crashed while I was on the interweb. Now, when i try to boot, it asks me to log in. Never had to do this before, and the 3 possible passwords that I use for everything don't work. I can log in as a guest, but of course I can't access my folders or documents. Any thoughts?
Okay, follow this guide: https://wiki.ubuntu.com/RecoveryMode, then get a root shell. Type in
passwd **your-username-here**. Set the new password to something you can remember, then type
This "feature" is a massive security hole, though it's also useful for legitimately getting into your machine.