Strange ghost images/display problems

I just bought a Power Mac G4 Cube, which is my first Mac, and I really like it except that I've been having a problem with the way it displays on my monitor. I have tried my older Gateway EVO CRT, which served me well with my PC, but on my Mac it looks terrible. It's difficult to explain what's going on, but basically when I have a window open, there is a semi-visible extention of it horizontally all the way to the edge of the screen. Also, the colors seem to be washed out no matter what adjustments I try to make on the monitor or within the OS. I've also tried my dad's LCD, with the same results. The only common ground between them is that I plugged them both into the VGA port. Should I look into getting a converter? Does anybody know why this happens or how to fix it?

You need a better quality VGA cable. I've had this problem before and the only way to solve it is to spend the money on a good cable. Upwards of $50 for a really good cable is not out of the ballpark.

So this is an ordinary thing that happens with all Macs? Or just the Cubes? Does going through a converter help? I'll buy a new VGA cable if necessary but I'd like to avoid it if there's anything else that can fix the problem. Thanks for the responses.

Things have gone from bad to worse...now I'm getting no display at all. Does anyone have some advice?