The Problem: On what has always been a perfectly good LCD monitor, you begin to see a faint but distracting "ghost image" to the left or right of desktop elements (like windows, icons, or black text on a white screen). Unlike the burned-in images associated with old CRT or new plasma monitors, this image is "live" -- when you move screen elements or change the contents of the screen, the ghost image moves and changes, too. The effect looks a bit like those slightly-offset ghost images you used to see on television screens back when t.v.'s were hooked up to "rabbit ears."
The Solution: The good news: it's not your monitor, or some obscure driver, or the video card in your computer. In most cases, it's the monitor cable. If this just started, you probably added some new electronic gizmo to your desktop, or the shielding on your current monitor cable has been compromised in some way. If the monitor cable is touching another cable, a modem, or even an inkjet printer, move the cable. If this doesn't fix the problem, replace the monitor cable.
How I Discovered This: The image on my 22" widescreen Samsung monitor -- always a great performer -- suddenly became smeared with a ghost image like the one described above. I tried all kinds of things, including twiddling refresh rates and downloading new video drivers.
Nothing worked ... but I did notice that the ghosts weren't present when I would hook my laptop up to other external monitors. This ruled out the video card (hooray!) but made me think something was wrong with my trusty Samsung.
Then, while thinking about when, exactly, the problem began, I realized I had added a new printer -- an HP Photosmart 3310 All-in-One -- to my desk at about the same time. Could it be emitting some kind of interference that would screw up the image on my monitor?
I plugged in my monitor. Ghost images galore. I unplugged the printer ... and, just like that, the ghosts were gone! In the end, in order to have both my monitor and printer on at the same time, I've had to move the monitor from one end of my desk to the other. (That was my zero-dollar solution; I could have shelled out the big bucks for a monitor cable with better shielding.)
This was such a simple fix, I had to share it here. Hope it helps you!