I am using desktop HP running windows 7. I had been using computer all day (including email client Thunderbird). I left around 8:45 pm cst to store (computer was left up and running). When I came back about 9:15 pm cst I "woke-up" my computer and tried to open Thunderbird to send an email. Thunderbird asked my to setup my account. What happened to my email / accounts ????

I did not run any updates today.