First off, you'd best get anything of value copied off of the laptop, pronto.
- Is there anytime when you can see the boot up screens? If you hit delete during startup, can you see the BIOS?
- I saw nVidia 8400, is that right? If so, have you updated the drivers? If not, download the latest version, do a custom install (select perform "clean install") and see what happens.
- Last effort, go to device manager (right click Computer, select Properties and Device Manager should be on the left), find the video card in Display Adapters, right-click and select Uninstall; then reboot, the computer should identify the video card and install it automatically. It might help.
Unfortunately, with a laptop not only do you have the monitor and video card as possible culprits, but the hinge also plays a factor.
Hope this helps.