Colour not working properly

Hello,
My windw is xp pro. I have a dell flat screen monitor E156FPF. The colour is not working properly. I have no red colour and the colours on my desktop are very pale. everything seems to be green and blue. I don't know what is the problem. Could it be due to the wrong cable? do I have to have special cable specifcally for this MODLE? I used the cable from my last monitor and it fixed well. There are also 3 keys or bottons on the monitor for colour change i suppose. But every time i press any of them I get a lock sign or feature on the monitor and no action. Your help greatly appreciated. Thank you