5 years on a monitor thats good My old monitor (Belinea) dated from 97 and has gone through everything from Win 3.1 to XP Picture is still at default settings
Reason for changing? The Power button broke (inaccessible to fix

)
Back to yours the fuzzy display could be down to the Tube being overdue for degaussing
Most monitors do it automatically on startup the Big click/boom sound you hear
Not hearing these noises?
Have you a button on the monitor that says OSD or
On screen display? Hundreds of possibilities
May even say Degauss or Demagnetise or a picture of a magnet?
If you can locate any of these select it and the screen will blank a big click and boom sound is heard and the picture returns (not broke anything)
Has it improved? May have to repeat 2 or 3 times if the display is really fizzy
PS The Manual degauss button is sometimes fitted either on the back of the Monitor or internally (on a very old monitor) if this is the case then a TV repairman is better able to carry out the job
