I reinstalled Ubuntu14.04 in my laptop (32 bit) since I couldn't update the system, unfortunately the problem persists. Basically when I type
sudo apt-get update, the system search for the sources and after getting them it just says: "Reading package lists ... Done" and then ends the process.
I used to see different messages like "Building tree information" and then "Reading state information" but now nothing similar appears on the screen and the system is not updated since typing again "sudo apt-get update" gives the same result (I was expecting a message like "The system is already updated").