this is a common problem but you need to determine where the drop is occurring
It could be your modem is losing its connection to the broadband network. Your modem should have a cable light that indicates it is connected to the network. If it is flashing when you lose connectivity, then read on.
If you are convinced your modem is good, you need to have your provider check the line for signal strength and the signal-to-noise ratio. The modem will lose communication with the provisioning server and network if the line signal drops below minimum, or if there is excessive "noise" on the line.
Maybe there is a tech here that can correct me but I think average signal strength or "power level" is about 3-5dBmV and average noise-to-signal ratio is about 30dB
The problem that most folks find is that these numbers can vary and power levels can change without notice. My modem goes down, the tech detects high signal/noise ratio and puts a line filter on it effectively dropping the signal and putting it within the normal parameters. A bandaid fix if you will.
Two months later, a change is made on the network, new switch, router or other head end equipment and the excessive signal now is corrected to within the proper operating window, but because I have the filter still on my line, my signal strength is below minimum and I get signal drops again.
What you can do:
Try removing any signal splitters off of the cable as these will reduce the signal. Remove any line filters that have been installed previously as they may fix a condition that no longer exists (including any at the PED). If you have an older modem, (ie, 3-4yrs old) while it should still work you may find better performance and better fault tolerance with a newer model.
A performance tip: the suggestion about ditching USB is a good one. USB is shared bandwidth between any other USB devices you have. Go with Ethernet and you will see better performance and reliability.
Hope this helps