This is one of the reasons I never really suggest monitors and always suggest going into the store and looking at a bunch. It may be that you have a bad (broken) monitor, it could just be the VGA cable, or it could (but unlikely since it is samsung) just be a poor quality monitor. I've you've seen the monitor in a store or at another person's house, then you'd at least eliminate one of the three options.
Anyways, factory settings are a decent place to start adjusting the monitor, but you should always expect to adjust the settings when you first use it in your environment. If you mess with the display settings you should be able to easily fix the green color issue, and may be able to make the image a little sharper.
Also, if your PC uses NVidia or ATI/AMD integrated graphics and you installed the drivers you can tweak the color and sharpness settings on your PC. Typically those settings can either be found on the control panel or by going to the advanced settings when adjusting the monitor resolution.
If you've tweaked both the monitor and the PC and still can't get it how you want, then it might be worth buying a cheap graphics card like the HD5450 which can be had for as little as $15 after rebate -
http://www.newegg.com/Product/Product.aspx?Item=N82E16814121444