Windows 8 display is Scaling down not maximizing the entire monitor

It isn't clear whether that is a full screen snapshot. If it is, the problem isn't that the image isn't maximized, it's shifted so you have a blank area on one side and the image is chopped off on the other. On an analog screen, there is a horizontal and vertical position adjustment to fix that. On a digital screen, if there are such controls, they don't do much except compensate for a few pixels that might be masked by the bezel.

It wouldn't hurt to look for a setting. Stuff like that is sometimes included in the "advanced" adjustments in the display settings. More likely, the driver isn't mapping the image properly to the screen. If you recently updated the video driver, try rolling it back or see if Lenovo has a new or replacement driver you can download from their web site (get it from Lenovo if one is available. If not, get one from the chipset manufacturer, which looks like it might be Intel).

I did a quick search to see whether this is a common problem and the only thing I found other than driver issues was one guy who had disassembled his laptop to clean it and fix a broken fan, and then he ran into a similar problem.