If you don't know how an LCD monitor works i will try to explain... there are three colors just like a CRT, Red Blue and Green, that are projected onto the screen. In some instances colors will stop working like in your case the red and blue quit and the green stays on. there really is no way to fix this.
ALL companies have a dead pixel policy. If there are more that 5(i think) dead pixels they will replace the monitor(depending on how old it is). in your case there are prolly about 768 dead pixels(depending on the size of the monitor). If it is still under the manufacturer warranty they will replace it.