Connection Issues. Wi-Fi connection

Within the three months of owning the computer. I have done nothing to its settings or changed anything on it. The computer refuses to stay connected to any source of Wi-Fi even using an Ethernet cord. I am at my limit and was going to sell after resetting the factory settings but even then there is something that is preventing it from resetting. I don't know what to do and I can't afford to take it to get fixed.