Inspiron 6400 Internet Problem

Hi all, I have a dell inspiron 6400 laptop. All programs are working on the internet apart from internet explorer. The laptop can connect to msn, but when I click on the internet explorer icon a message comes up saying that a program has caused the problem. I have tried installing firefox onto the laptop, and even that doesnt work. I have tried doing a system restore, but the furthest away restore point is only 7 days ago, and I was having problems with the internet then, so that didnt work. I have also tried using windows update and have updated all the necessary programs. I really urgently need this fixed so if anyone has any ideas please reply.

Thanks for all your help.