[aiharkness]

Have you dropped it?

Gotten it wet? Exposed it to moisture even in the form of a sweaty pocket, humid shower/bath room.... It doesn't take much sometimes to cause issues.

If you use a microSD media card, it would be a good idea to remove the card for a while and see if it makes a difference.

What about software? A third-party theme or application could be the culprit. Also pay attention to any apps that you are running that are set to operate in the background when closed. Given the crash just after entering your password, consider apps that are set to run when the device starts. If you are running a third-party theme, switch to a stock theme for a while as a test.

And free memory.... Open the options > status screen and take a look at files free. If it is down below 20MB immediately after a battery pull, then increase it by deleting or moving applications and media files from main memory. Put media on the microSD media card. Delete applications you don't need.