I have a desktop Lenovo Workstation S30 computer with an LCD screen. Up until recently, when I don't use the computer for about 20 minutes, it went into sleep/hibernate mode until I moved the mouse. When it did so, I would get a beeping sound. Now, I get the beeping sound, the screen blacks out for a second, then comes back on… And it beeps again. It doesn't go into sleep mode. What is causing this and how may I fix it? Thanks.
Added (1). I also use Windows 7.
Read more: How to enable my computer to get into sleep/hibernate mode when it is not in use?
