I would try the monitor on another machine if at all possible, even a laptop and see if it has the same effect. It may be your graphics card you see.
When the Monitor is on and working ok does it seem mis-coloured or hazy? Anything out of the Ordinary.
I would look at your Graphics card before jumping to monitor as the Fix. Espically if its an integrated graphics. You can pick up a GC for £20 / $40 which is a lot cheaper than a monitor.
Generally Monitors are either working or dead.. very uncommon for the symptoms you mention.
On another thought make sure there is no break in your monitor (VGA) cable.. replace it to be sure. Only a few £ or $
Philbert, August 2007