Flat screen televisions can appear "fuzzy" in a variety of circumstances. In most cases, the fuzzy image stems from running low resolution sources into these high resolution displays. Replacing an older tube television with a new flat screen without addressing the resolution of the sources going into the set is a recipe for disappointment. Given that high definition televisions display but do not create high definition images, a source and connection audit may be in order.
Replace standard cable connections with digital or high-definition cable boxes. Connect these using HDMI or component video cables. Enter the device's menu to raise the output resolution to the highest that the set can handle. Consult the manuals for the device and display for specific button press sequences.
Examine the back panel of all connected devices. Replace yellow composite or screw-in coaxial cables with HDMI, component, or S-video cabling, in that order of preference.
Set the cable or satellite box to only output the high definition version of channels where the standard definition version is also broadcast. Consult the manual to determine the best method to navigate the menu to accomplish this task.
Press the "Aspect" or "Zoom" button on the TV's remote to exit any stretch modes that may be in use. These modes also enhance the visibility of picture noise and artefacts, especially on low-resolution broadcasts.