As LKP mentioned AdBlock is pretty good at what it does. If you want more control you can also check your router as some of them have built in parental controls. You should be able type 192.168.1.1 into your browsers address bar and log into your router with:
username: Admin
password: password
Otherwise you can check the documentation. Good luck.
EDIT: And now I see this thread is almost 2 years old...