Web Pages not loading

[VoodooLily]

I am posting this for a friend of mine. I will be try to be as clear as I can.
-I did a search and couldn't find anything that helped at all.

He's owns a MacBook Pro, earlier today he was able to surf web pages just fine, after playing a game on History.com his internet connection became very slow. Now some web pages will not load at all. Select few will load but it takes awhile for it to load the entire page. Google loads very slow as well.
He is able to connect to the internet with no problems, Instant Messenger services work without any issues.

He has tried restarting a handful of times, resetting Safari, clearing history, cache, and everything else he can clear. He has tried restarting and resetting his router, and modem, and nothing has remedied this.

I'm not all that familiar with Macs, so if I am missing information that will help remedy this, please let me know and I will ask for it.

-Running OS X 10.5(Snow Leopard) (as far as he knows)

Thank you in advance to anyone who can assist me(us) with this problem.

[DICKSTER]

Voodoolily--try zapping the pram to reset your settings.. >Hold down the comm.[apple key] [option key]>P and R keys alll at the same time that you do a restart> Hold them til you have heard 3 separate sets of startup chimes. release keys then and let it do a restart.This may get you set right. Good Luck
Dickster---------------------