Laptop delivers blurry image to external monitors
Couple of possibilities:
VGA cable is of poor quality. Find a good quality (usually THICKER) cable with ferrite cores. It could also be that you are running the cable too close to power wires - power wires will cause interference, especially over long distances, with both VGA and network cables.
Laptop(s) may internally have poor quality electromagnetic shielding or are just plain bad. I've seen this many times in multiple laptops. Usually the DAC's (Digital to Analog Converters) are to blame, other times it is the cramped spacing of components inside the laptop causes interferences that manufactures "let slip" for whatever reason.
I find that using the "Auto adjust" option on the external monitor helps a lot.
It bounces around a bit trying to optimize the image display, and it works well in most cases.
This can be caused from interference from the power supply. Unplug the AC adapter to see if this is the case. If so, replace it with a good quality aftermarket AC adapter.