Try the monitor on a different PC, it may be the monitor that's the
problem rather then the VGA out. Presumably a laptop you are using or
is this a secondary VGA port on a desktop ?

On some computers, it was necessary to have the VGA plugged in at
power-up/boot-up for it to perform correctly.
Apparently some drivers need to be able to scan plug-and-play monitors
for parameters when boot-up is being
performed to get things set right.

Is there something on top of your VGA? Is there a fan on or magnet net to it?
How old is it? Some of the newer laptops will not work with simple VGA. Flat LCD
or Plasma monitor yes. It is is a old VGA. The laptop may not support that type
of pixels of the old VGA.

Have you updated the drivers through Microsoft Updates under Optional? Perhaps a
hardware go between might help, it would have multiple ways to connect to TV or
monitor?

my last reply assumed you were under Windows, although, it could be a
mismatched VGA Â driver setting. I suggest trying a Pupply Linux Live CD to see
if the laptop works better with XORG or VESA driver...then research from there.
The hardware go between is for either OS.