Other things I’ve tried - opened it up, reseated keyboard and mouse cables (with antistatic wrist band on). Replaced keyboard with a different one from the same model laptop. Same issue. I bought this laptop second hand knowing the screen had gone (it was on but only partially displaying). Replaced the screen. Screen is fine. Just the keyboard and mouse not working now.

So is it - failing Motherboard, boot/bios virus, or possibly liquid damage to parts of Motherboard? I know that can make a screen and keyboard partly fail. But the fact the keyboard works in the bios is the strange bit.

I have been told I either have Motherboard beginning to fail - or a bios virus? Everything powers up but keyboard and mouse don’t work once past the bios. There are two hard drives - one soldered to the Motherboard which was the original boot drive and is not showing in the bios. The second one is fine. The second one has been wiped with parted magic (cant even use keyboard and mouse in parted magic). I can boot linux live but can’t install due to no functioning keyboard. Have used Kaspersky rescue disk via usb to virus scan and nothing found (used a usb mouse to do that). But it can’t virus scan the non showing disk because it’s not showing. So is this a sign of a damaged or failing Motherboard or possibly a virus on the non showing driving (boot virus?). I would try flashing the bios but am now concerned about transferring viruses via usb so have binned the usb stick and don’t want to keep binning usb sticks!