Could be possible that the NiC (USB Network Adapter or PCIe adapter) is going bad, or it could be the router itself. I would test your network adapter in another computer and see if the issue continues, if it does just replace it. Like most people will say, going wired is better. If you do not have the ability to run ethernet in your house, I would look into MoCa adapters. You would need two adapters for about $140, and it basically just piggy-backs off the coaxial lines in your house and sends data through them, and its almost as good as Cat5e.