Internet Explorer crashing

Whenever I close down a window explorer closes down and I get error messages and it only closes down whenever I close a window other than that it runs fine, almost I have ran varies anti-virus scans, gotten rid of temp files and old shortcuts, run scandisk, defrag and even Norton to see if I could find the problem. It does not close down the computer but it closes down the internet. Right after the close down it runs very, very, very slow. I have an error meassage text file if you would liketo see it. I have been trying to write down what I was doing and the times that it happens and error messages, so just let me know if you want the file.