Not too familiar with monitors but it does seem like one of the colour guns has failed. Please wait for further confirmation on this though.
Couple of things to try are, have you got a degauss button on your monitor,if so give that a press, see if it helps. If you can try your monitor on someone else's system it will establish if it's the monitor or your card.
Are you sure you only have a 12 month warranty? Even though most systems come with 12 months, the monitor is usually separate with a 3 year warranty.
Post back with the make/model of system and the monitor and was it bought from one of the well known suppliers? It's OK to name them in your thread.