I use a Dell inspiron n5110 laptop with 500gb hard disk space and 4 GB of ram. Recently I thought of changing my os from windows 7 home basic to windows 8 . I used a USB drive to install it on my laptop via custom installation procedure. The installation was complete and the laptop restarted. I even got the windows logo with " getting devices ready " messages. But i got a black screen after that . Since it took too long I pushed the power button off and turned it back on . But the problem persisted . After repeating the same process I got a blue screen with an error message "page fault in non paged area" . I could not boot into safe mode too. I can't get past that black screen . I even downloaded a new iso image of windows 8 and tried installing in my C: drive after formatting it. The problem persists even now. And I can't format my whole hard disk as I don't have any backup for the data. What should I do ?