So today I left my computer for 30mins. Got back and couldn't find a logon screen to log in. All was display in front of my monitor is just my desktop wallpaper. I can move my mouse around. I try right clicking on my mouse and nothing show up. Try CTRL+SHIFT+ESC or CTRL+ALT+DELETE and still nothing show up. So pretty much I had to hard reboot it. I set the screen saver to none and have it set to 21 mins after idle and On Resume, display Logon Screen. This is the first time this happen and I don't know if it's Windows 7 Build 7600.16835 bug or something else. Really weird.