My Ubuntu is not working after updating

I have installed ubuntu 12.10 alongside windows 7 home premium using wubi.exe in local disk.Recently I installed some apps from software center.Then I installed the updates (around 275MB).After that I installed code::blocks before restarting.Then I restarted my laptop.My screen was just blinking.Even the login window was not displayed.

Again I uninstalled Ubuntu and installed it in a separate drive which I partitioned for ubuntu. I installed the updates immediately on rebooting.On rebooting after installing the updates ,the same problem happened again. What should I do now?