Citroen Xsara Picasso trouble starting

I been having starting car for last few weeks, sometimes can start first time sometimes takes about 5/10 attempts before it starts, last night just wouldn't start and had to leave it, few people telling me starter motor or battery but when tryed one last time to start it on lights came on on the dash board and the information but when turned lights on this all went then when turned them off again it come up on dash board ABS FAULT NON-FUNCTION I'm confused to what it is? Also sometimes once it does start smells petrol and even when working well when have window done and driving you can always smell petrol?