I tried to install windows 8 on my sony vaio. The installation didn't complete and the screen went off. I put it on again and it gave me this message \WINDOWS\SYSTEMS32\CONFIG\SYSTEM and that i should attempt to repair this file by starting Windows setup using the original setup Cd-Rom. Also select r at the first screen to start repair. How do get to fix this problem

No such thing as Windows 8 (yet). Please explain.

Note that notebooks are very proprietary and so you should probably use the recovery methods established by Sony to take the notebook back to the factory state. Then, before upgrading to a newer version of Windows, make sure Sony has drivers for your notebook that support the newer Windows. If no drivers, do not upgrade Windows.