I see two variants: first is problem of your computer (viruses, old windows running not as good as you want, wrong presets of operating system and hardware network, browsers, etc) second is problem of your ISP (internet service provider). You need check your computer and if you are sure it's ok (if you don't know computer very good you will maybe need help from people who does, friends from your location for example:) you need call to your ISP and ask him about your problem with low internet speed. But Before I recommend you read your conract with ISP especially about guarantee of internet speed.