Agree with Conan.
Unlike CRT monitors, which can run at any resolution up to their max, TFTs are only really happy when they are at their "native" resolution.
For a typical 17" TFT that is going to be 1024x768 or thereabouts.
Ghosting can also be caused by using a poor quality VGA cable (15pin D-SUB) rather than a DVI cable. TFTs were designed for input with DVI. The VGA socket is only there for backward compatibility and is seen as the "poor man's connection".
In the real worls, this means that most people need to upgrade their graphics card as well as monitor, as most older PCs (and quite a few new ones) still only come with the common garden VGA connector
If you are stuck with a VGA cable, then maybe try a new one (which can be picked up from PC World or Maplin). I would try the other advice first but ultimately, when you have fiddled with all the software settings, it is time to start debugging the hardware. The cable is the most likely (and cheapest) culprit.
Regards,
Shuttlebus