Crossfire crashes the internet on my computer

Hi this is Aerodu, trying to let more people play crossfire.
A good friend of mine has a pretty good vista vaio laptop.
Everytime he tries to play crossfire, the starting screen only shows the buttons, the pictures are always white. and when he clicks start game, the internet crashes and he has to reboot in order to use the internet again.

Personally, I'm a computer techie, but I don't use vista, and have no idea what's wrong with his computer. I think it's the firewall disabling crossfire, but I enabled it and still crashes the internet...

He also tried playing other exe files that require internet connection such as hamachi.
also games like soldier front, maplestory, combatarms,..... Any Online game on his computer crashes his internet...

Can anyone help?