Black screen looks blue? Wow, that is weird. Black should be black on all CRT -- no electron hitting the screen will give you black. Don't know how could it be possibile.
Some suggestion though:
1. adjust the color temperature. this affects the "color" of white area.
2. increase the contrast to 100% and decrease the brightness so that the black area as dark as possible. this affects the lightness, but not the color.
3. adjust gamma (I use Adobe Gamma loader, which comes with Photoshop. Don't know whether it is downloadable or not.) This affects the color of mid-gray area.
If none of these works, well, you know you can't expect too much from a $100 21" monitor
