This particular emachine model is known for having defective usb ports. It is not a software issue, the ports are physically defective and literally fall apart into pieces and/or fall back into the machine where they cannot be used.
This happens just with ordinary use, it may not be your son's fault. Please research this further on the internet and you
will find many other similar reports, also look into the reviews of emachines on trusted sites.
If you contact the company they will advise you to have it repaired for $400. The computer may not have cost much more than that and you get what you pay for sometimes.
One person reported success by soldering on a new usb port but encountered many difficulties in the process.
I tried a very low tech solution. Shortly after purchase, one of my usb ports had disintegrated and I ignored this until the other one lost function several months later. (The machine continued to report the devices working properly.)
Before it completely disintegrated I opened the case and pulled it forward enough to attach to a hub and then secured it with electric tape.