USB connection issues



I have an HTC One, and am trying to sync music to it. I have the HTC Sync Manager installed and up to date. When I plug my phone into my PC the phone charges, but does not connect via USB, it has been hit or miss in the past, and has been a whole lot of miss recently. My computer does not "see" the phone as a device at all. Help! Please! And thank you in advance for any help you can give me!