Regarding Apple products:
- About LCD display pixel anomalies for Apple products released in 2010 and later
- About LCD display pixel anomalies for Apple products released before 2010
Different type of problems:
Here are examples of screen problems picked from HP support. Visit their excellent guide for further information. Here are some highlights.
The screen is unsharp or stretched.
It may be so that the computer resolution do not match the screen resolution.
- Restart computer
- For Windows, change screen resolution to the one recommended for
the screen by right clicking on background and pick the correct one.
- For macOS, open system preferences and the screen tab and change resolution to the one recommended for the screen.
Some pixels are dead.
The vendors usually have certain amount of allowed dead pixels on a screen. In practice one often have to live with it if the number is low.
There are vertical or horizontal lines permanently on the screen.
This is a hardware problem that cannot be fixed without replacing the screen.
The screen is bleeding along the edges or corners
- This is a hardware problem that cannot be fixed without replacing the screen or parts of the screen. If it is really bothering then get a new screen.
- For old thick CRT-screens disconnecting the screen over the night could help. However, for modern LCD/LED-screens we have still not heard that that should help.
On Mac, colors in the background is bleeding through front window
The Yosemite GUI introduces transparency for window. For example here in Safari top of window (red) and right side (brown):
Fix by activating Reduce transparency in Accessibility preferences.