Your son probably picked up a virus or other nasty network cridder.
Suggest you first turn off the computer for 30 seconds or more. If you have a bug in the memory. Turning the computer off should eliminate it from the memory. Thirty seconds allows the capacitors to drain thereby removing all the voltage from the computer thus the means for the bug to survive in the memory.
Next, if you can, boot up in the safe mode.
If that worked, boot up in the safe mode with internet capability.
If your still running good, go to
TrendSecure | HouseCall™ Free Scan
and run the Housecall antivirus check.
This should either catch your bug or give you a clean bill of health.
At this point, you either have a good computer or you need to come back here and let us know exactly what you did and what the results were.
If this works, then you probably don't have an antivirus program on your son computer or it is not up to date. Hint.. hint.
Good Luck...