I have a new HP quad-core. Windows has suddenly started "logging me out" after about five minutes, sending me to the Windows 7 log-in page. I have to re-enter my password and then a can resume the task or website where I left off.
Actually, it logs me out after about one minute of inactivity, even though I have it set to go to sleep after 30 minutes of inactivity. Screen says "Rob Harman" is "Locked" and has me re-enter my password.