My phone cannot be recoginzed and cannot connect to my computer. Need help please.

When i attach my phone to my computer via USB port, nothing happens and the files on my phone do not appear on my computer. I need to download some music onto my phone but i cannot find my phone's files. What can i do to fix this problem? help

Edit: Never mind i fixed it. I had a second hand USB charger so i just had to replace it for my computer to recognize the device.