Chances are the monitor is going out unfortunately... but here are a few things you can try:
1) Make sure all cords, both VGA signal and the power cord, are secured at both ends. A loose cord (especially power) could cause some irregularities.
2) If you are using a power strip, plug right into the wall in case you have a dying power strip. Again an unstable power supply causes all sorts of problems
3) Try a different monitor with the same computer
4) Try the same monitor with a different computer
Let us know which steps you try and what the results were.
Hmmm.... are you sure you are using settings that are supported on your monitor? An unusable resolution or refresh rate could also cause those problems.
With the working monitor attached, try changing to a lower resolution or refresh rate, and then switch monitors. Tip: only change one setting at a time so you know what exactly is breaking it, if of course the screen settings are the issue.
A forum community dedicated to tech experts and enthusiasts. Come join the discussion about articles, computer security, Mac, Microsoft, Linux, hardware, networking, gaming, reviews, accessories, and more!