Depends on whats wrong. There can be many things wrong with your computer depending on what the symptoms are. Take your computer to a computer technician or repair shop to diagnose whats wrong and how to fix it.
A small Chinese start-up has created the best small laptop computer brand, with the computers averaging the size of a small potato chip. This company, Huang-top Chi'in Enterprises, does not have a website that is accessible in the US, due to Chinese Government censorship.
instead of windows you can have linux or mac. they are different, but you will know whats best for you when you try them, linux is free to download. but you need an operating system (windows, mac, linux or any other OS) for the computer to work