It seems that the Raspbian image is damaged. because I tried Pidora and RISC OS through NOOBS and both worked flawlessly. So can anyone advice how to repair the Raspbian image on NOOBS.

I bought a RPi Type-B with 512 MB RAM from RS Components, along with the pre-installed NOOBS on a 8GB SD Card. After connecting and powering up I get the menu of NOOBS wherein I am asked to choose the OS I wish to install. I choose Raspbian and It gives me a message "Image successfully Installed". H...