Computer display suddenly blurry/corrupted. Sometimes crashes


I have a Dell Dimension 420 that has suddenly developed what I am calling a “blurry” screen.

  1. First: Screen went all pixelated:

    pixellated screen

    Mouse would no longer move (laser still on), and keyboard CAPS lock would not toggle or illuminate.
    Windows Side Show on the case LCD ceased responding (said something about could not communicate with Windows). No blue screen. Had to power cycle.

  2. Second: Above symptoms repeat after ~5 minutes of normal use after booting.

    desktop after minutes of use

  3. Now: Seeing blurries even when in the BIOS, Windows repair screens, and Windows logon.

    bios screen

    windows repair screen

    windows logon screen

What I have tried:

  • Replacing monitor (with a spare)
  • Replacing all monitor cables
  • Sadly, I have no on-board video card (or spares) to test with

I almost assume it is the video card (since the problem is in BIOS too) except when it initially also affected the keyboard as well.

Misc machine specs:

  • 32-bit Windows Vista Home
  • 3 GB RAM
  • E6820 processor
  • Video card – standalone, DELL G92 HMGA16
Asked by Chris Anton


The system locking up the first time you saw the failure would tend to indicate your system is overheating, and that the normal hardware protection for such a situation has not worked as expected – fans have not ramped up their speed, and the CPU and GPU may not have dropped their operating speeds to allow themselves to cool.

If your system BIOS has a health-monitoring screen, check your recorded temperatures – if they are high, you have a definite overheating problem.

Verify that all fans are running, that air is flowing correctly through your system, and that your air intakes are clear of contamination. Verify that all heat sinks are also clear of contamination – if necessary clean with a can of air-duster.

If everything is clean, airflow is good and all fans are running, then I would suspect a faulty video card – but not until ruling out temperature and contamination as a source of the problem.

Answered by Mike Insch