Can ping but can't browse or game - Windows 7

Is this computer on a router? Do other computers on this router have this problem? If yes,
Make sure your router set to be dns server. In your pc setting for network make sure your not using a fixed ip or dns. The auto ip and auto dns buttons should be selected. Under networks make sure ipv 4.0 and ipv 6.0 are installed.
Good luck.

Thanks - I updated the initial post.
Yes, the other computers on the network (same router) have full internet functionality.
On the problem computer, IPv4 and IPv6 are enabled, and there is no hard-coded IP address or DNS server.

OK, so it is computer specific. When did it work? When did it stop working? What was done in between?
It's highly possible a system restore point prior this occurrence can be used.
Again I emphasize greatly the need for full system image backups frequently for just such cases.
I screw my computer up all the time trying and playing with new things but restores in minutes.
Don't know your son's usage but very possible to be infected with some malware do to gaming.
If system restore works run your malware scanner or an on-demand scan from Malwarebytes or
similar scanner program like Superantispyware before continuing.
Good luck.

It stopped working about 3 days before I posted this thread, after he ran MalwareBytes. Apparently he had not set any system restore points. Once this is resolved you can bet that he will. Still not resolved, would appreciate other ideas. Might there be other firewalls running?

do you have any security software running especially norton or mcafee?? AV/Security software can be the problem. Sometimes even running in safe mode doesn't disable these things completely.

Restarting in Safe Mode did not help. I'll see about disabling AV stuff temporarily.