Malfunction goods bought at Lewis store.

Bought a laptop from Lewis store Orkney last year, after a month after receiving the laptop it was malfunctioning, I took it back to Orkeny store where they took it to technician, it came back after a month but it was still malfunctioning. I went back and forth to the store and no one helped even the store manager so I left the laptop at the store until the problem is solved. It's been 3 months since I left the laptop in store still nothing. I asked what is the policy for malfunctioning goods especially high tech products like a laptop. No one answered me. I had a similar problem with a refrigerator which I bought at the same stored it was fautly and it was replaced, why can't the replace the laptop?