Faulty Lenovo Laptop (Hitchin SG5)

It works fine - as long as it remains plugged in. Remove the power and it crashes immediately. I don't think it's a battery problem, more likely an internal fault. Details are:

- Lenovo G710
- Intel Core i7-4702MQ CPU
- 8GB RAM
- 1TB HDD
- Windows 10 Home Edition V1803
- 17.3" screen, 1600x900

It has been reset and is ready for a clean setup.