Why is it showing that someone else tried to log into facebook using my computer, but I noone has ever used it?

[poetgirl]

I'm the only one who uses my computer, however when I went to facebook to try and login it was showing about 4 other different emails in the drop down box when you login, as if someone else was logging into their account using my computer, how does this happen. Absolutely no one else has been able to use my pc let alone 4 different people. They each had a different email, one was yahoo, another was netscape and another was aol.