Screen has back light but nothing else loads

Hi, I have a Sony vaio SVE151D11M laptop.

Yesterday the keyboard started playing up and not working - wouldn't type and the caps lock light etc wouldn't work. The assist button did work. And the touch pad worked.

After looking online I uninstalled the keyboard drivers and restarted computer. When It loaded back up the screen lit up but nothing showed on it. The power light and wireless light comes on but again nothing happens

The processor light on front comes on for about 5 seconds then goes off and doesn't come back on.

Read online again this could be a hard drive issue so I reseated this, but had no benefit.

Any clues?