I don't know for certain.
But the Internet has not changed, and if it did, everybody's computer would crash. only yours does. That pattern suggest, but does not definitively implicate your RAM memory.
By far the easiest way to cause poor performance, instability, overheating and crashing is to install ANY third-party speeder-uppers, Cleaners, Optimizers, or Virus scanners, or a VPN that you installed yourself. The main reason is that they are relentless in scanning your files, non-stop, looking for virus-like patterns in Everything, or looking for files that have changed. When completed, they do it all again.
¿do you have anything like that?