2006 Audi A6 ignition problem please help please
 

i have 2006 audi a6 a week ago i faced a problem i turned off the car n i took out the key everything is ok but once i wanted to turn on the car it does not work at all even by the button its like completely off n when i asked about it one of my friends told me that i have lost the code of the key, is this right? and if it right how should i solve this problem please i need ur help people.
Thank you.