[ubuntu] Laptop screen flickers or just does not show.

Hello, I am fairly new to Linux, so I don't know what logs I am supposed to look at for this issue. I hope you can point me in the right direction. Here is the situation. I have installed ubuntu as a second OS on my previously only windows 8 machine. This is a 64bit Ubuntu 12.10 on a Sony Vaio. I did this at work, so while doing the installation my second LCD screen was also connected. During the installation, everything was working fine. That is I could see on both screens properly. Even after the installation, I was able to split my desktop with each screen showing a different resolution. And everything was fine.

The problem started after one of either I did a software update (the one prompted by ubuntu) or after doing a boot-repair. I was not able to load back into my windows environment, and by the suggestion here (step 5). Now I can load my windows 8.

The problem now is that my screen on my laptop doesn't display anything. If no external monitor is connected through VGA, then the screen just flickers like crazy. If I do connect an external monitor then, using the keyboard to switch screens, I can make it so that the external monitor display is normal. This only works in the setting where the external monitor and the laptop screens are showing content, but are not mirrored. In any other setting, both the screens start going crazy. If the laptop screen is set to not display then external lcd screen goes haywire.

Please help me out with this problem, let me know what kind of logs I can provide.

Thanks