Hi Bebop
As Mac says this is definitely a graphics problem
If you can see the Bios and Boot up screens OK then it most likely a corrupted driver, however if the Bios/Boot up screen does not appear, then it is hardware, and requires the services of an engineer. (It may even just be a dodgy connection to the screen/connectors)

The Engineer will also be able to repair it without losing any data.

If it is beyond economic repair (It seems to be getting on a bit) the engineer will be able to copy all your data to an external drive which you can access using another computer.

You can also buy adapters to plug the Laptop HDD into (It’s normally just a couple of screws to remove) and copy the data yourself.
Hope this helps

Bill