Since he's using Chrome, he could disable his add-ons. Mike says he has problems in other browsers too, though. Leo suggests checking his global settings in Windows, and reset the security levels to default.
Failing that, Leo recommends creating a new 'dummy' user account on the computer. He can log into that, and see if the problem still exists there. If it doesn't, then he will know it's something in his user account that's preventing the comments from loading.