When you switch on your laptop, can you see VAIO logo on screen?
if yes, try to connect your laptop to external monitor.
if not, is the NVIDIA BGA chip faulty, it is common in this machines.
If you can log on to safe mode, you can do a right click on computer>Manage>Device Manager
look for Graphics adapter and click on top nvidia than delete it. Reboot and let me know.
If you have a monitor or can borrow one, hook it up to computer and see if that works. If it does, roll back the driver up date.
Yes, I see the VAIO logo, then I see the Windows logo and the login screen looks fine--just moves a little slower. As soon as I type in my password to log in, the screen go black and I can't see or do anything but hard power off.