Lately I've had a problem staying logged in all day, even when I do not turn off the computer. I login in the morning, being sure to check the box first that says "stay logged in" then actually clicking the login button. But I have to sign over and over again throughout the day. What's up with that?

Is it dependent on keeping the same browser open all day, too? I have checked to allow cookies, but what else might I be doing wrong?