Citroen Xara wont start even after new alternator ?

Hi, My Citroen Xara Picasso Y reg petrol had a bit of a rough ride last year with a connection fault on the battery. We have had the connection changed to an old style one and the car was working ok. Then it decided to not start, i charged the battery and got about 10 mins out of it. This resulted in a new alternator on Saturday. I then got told by the garage that the fan was not working and they wanted me to pay an extra £100 to fix it but i said no i would take it home and bring it back next month. The car started at the garage and kept cutting out but i put this down to the fact it was sitting still for a couple of months and when i got it started and revved it worked OK. I brought it home, took the battery out and charged it over night. When I started it this morning i got nothing just a little hugghh sound and nothing. The lights and everything else are working but the engine just wont tick over. I really cannot afford to go back to a garage who want to charge the world f it is something i can do myself. i have cleaned the earth connection to the battery as i was told it could be that but no change.