Easycleaner is a small free program that will clean up your registry and some other things that will slog up your machine ~ it helped my computer quite a bit. easycleaner
It sounds like a hardware issue, particularly with how is fan is going nuts suddenly and how his issues kick in when using something like video.
You're probably right, but he should start with the small stuff (spyware, registry, viruses, trojans, keylogger, etc) and work his way up.
