Why does the screen look so lousy?

I purchased a new laptop off the internet, sight unseen. Now that I have seen it, compared to my previous laptop, the screen is much less sharp and clear.

My previous laptop, where the screen looked quite good, was:
15.4” WXGA High-Definition BrightView Widescreen (1280 x 800) Display

The new one is:
15.6" Diagonal High Definition HP BrightView Display (1366 x 768)


...Would just the difference in these two specs account for such a noticeable difference in the the resolution of pictures or videos on the respective screens? Or other factors come into play?

Anyone know?

 

There are many factors besides just the resolutions that affect quality, including,

Bandwidth
Signal (from the graphics solution)
Cable & connector quality
Sharpness & Focus
Electronic component stability​

And don't assume because both say HP High-Definition BrightView that both monitors will have similar characteristics - they may use totally different technologies from different makers.