Does your son play on the same computer with the same link to the internet??, if not it could still be either, but presume your household has a network in which case yes your computer looks likely as you say, so yes try experimenting BUT WRITE DOWN EVERYTHING YOU DO and do one thing at a time, then if same issue persists restore it. I like to put things in simple terms initially, your picture is stuttering, so there is a bottleneck somewhere, or interference, stopping the information flowing correctly and fast enough to your picture. Now this could be a number of things,start with the programme itself then progress to the computers software and last of all the hardware. If you are unsure of what you are doing, especially if interfering with the OS or hardware then do not do it, better safe than sorry, do not touch the bios unless you are absolutely confident in what you are doing, remember one thing at a time if that doesn't work put it back.