rezapanahirad

my c5 is 2006 there is a big problem happened for me: engine was working good but suddenly stopped and after that don't start . when I change the position of car switch to start , nothing happened and after 2 second high speed fan is start to working. on multifunction display write: economy mode and I have check the fuses under steering in the saloon and all of them are ok. please help me this is a big problem and I don't know what can I do? which part of vehicle maybe cause of this problem? I must comfess that problem is happened after I install xenon light on front of car and as soon as I turned on xenon this problem happened. please help help help thanks