I’ve been using a second-hand 15″ TFT monitor for just under two months now, and today came into a large, 17″ Medion SXGA screen. And my goodness, does it do the job well. I’m typing this now at a 1280*1024 pixels screen resolution, and the text is crystal clear, sharp and well-defined.
But it wasn’t at first. It was, when first plugged in, fuzzy, out of focus, cutting off around a tenth of the picture and had washed-out colours. And many people when buying a TFT for the first time probably don’t understand the reason for this.
There is a reason - it’s because the monitor is below its native resolution. The native resolution is the minimum screen resolution the screen can work with without the image appearing blocky or fuzzy. Normally it’s the highest resolution the monitor is capable of as well.
If your monitor appears mysteriously fuzzy, it’s because the screen resolution is set below the native resolution. You need to compensate for this by increasing the screen resolution.
In Windows, this is relatively simple (for something that Microsoft wrote not too long ago - my goodness…) - all you have to do is go to the Display Properties dialogue box (right click the desktop, select Properties), switch to the Settings tab, and drag the ’screen resolution’ slider as far to the right as it will go.

Now click the ‘Apply’ button and wait. The screen may blank or flicker for a few seconds, but don’t scream and pull your hair out - this is only because the computer and monitor are adjusting themselves to the new settings.
Then, when your desktop reappears, if it does, click the “Yes” button within fifteen seconds - otherwise the machine will revert to the old resolution.
In Linux, if you’re not using a desktop environment that has an applet to control screen resolution, like the one in KDE and another in GNOME, you’ll probably need to edit the x.org configuration file - see your distribution’s documentation for information about how to do this.
Things to bear in mind
Note that you need to be careful when picking resolutions, in particular when it comes to the screen’s aspect ratio. Normal, non-widescreen monitors use the aspect ratio 4:3 (four pixels across to three pixels down). Widescreen monitors use roughly a 16:9 or 16:10 ratio. If you pick the wrong ratio for your screen, it’ll make the image appear squashed and probably break your screen as well.
There’s a simple way to work out the aspect ratio of a resolution - use a scientific calculator to simplify the fraction of the first number over the second number, eg 1280 over 1024. You could also simplify it by hand if you wanted.