4.What is the difference with Matte and Glossy screens.?

 
 Please, take a look at the picture below to compare glossy and matte screens installed in the same laptop:
glossy and matte
Left - glossy, right - matte.

 Glossy and matte screens are absolutely interchangeable and it's just the type of the screen surface.Traditionally, laptop screens have had a matte anti-glare finish to scatter reflected light. This has the side effect of scattering the light from the display, increasing blur and reducing contrast ratio, color intensity, and viewing angle.Glossy screens use an optical coating to reduce the amount of external light reflecting from the surface without affecting light emanating from the screen. Their shiny surfaces still reflect more light than matte displays, but are less reflective than an uncoated glossy display would be; reflections of external light sources are not diffused by glossy displays, so certain lighting conditions tend to favor a traditional, anti-glare screen. In controlled environments, such as darkened rooms, or rooms where all light sources are diffused, a glossy display may be more enjoyable for the viewer.
   Glossy displays create more saturated colors, deeper blacks, brighter whites, and are sharper than traditional matte displays. This makes these types of displays more appropriate for viewing photos, watching movies, or even just general computer usage such as web browsing. Also, in extremely bright conditions where no direct light is facing the screen, such as outdoors, glossy displays can become more readable than matte displays, because they don't disperse the light around the screen (which would render a matte screen washed out).

TIPS:Most display manufacturers label their glossy screens under a variety of brand names: 

glossy screens under a variety of brand names