I have recently installed the lastest raspbian jessie version and it has worked fine. the raspberry has boot correctly and the graphics mode is OK. Then I have started to configure my wifi usb adapter and the raspberry pi camera. After a few reboots to check (first I have installed the wifi adapter and then the camera) where the raspberry has been launched correctly, the boot is not done. I mean, the raspberry is on, I have all the boot messages in OK but the graphics mode does not appear. Instead the screen is black with the cursor pointing at the top left. It is impossible to set any command or to login with a user.
Do you know why this happen and how could I solve it (I imagine as last option I can install again the OS in the SD card)
I am using a SD 32 GB classe 10 and my raspberry is a B model.