What's wrong with my computer?

I have tried to connect it to the internet (via WiFi) without success many times. I don't remember any time that that pc worked with WiFi, but the internet worked always at my father's house connected by cable to the router. The thing is that I tried to connect it to the router too without success and I don't know why it doesn't work and what to do to make it work.ALSO, my other computer use to work very fast and my internet connection was always excellent, but recently it changed and now is SO slow and it doesn't work even connecting it to the router. Does anyone know what could be the problem? what can I do to solve it?(Sorry for my bad English, I'm from Russia) via /r/technology http://ift.tt/2uplD42