Internet Explorer Problem

I'm experiencing several problems that may be related.

1. When I try to order goods from a vendor (not Norton) it fails to advance to the "Cart". This is happening on 2 different sites I know about.

2. Quite often when I try to link somewhere else I get a msg. "Internet Explorer has stopped working" and goes to another msg saying Explorer is trying to fix the problem. After a substantial wait I have to click on the "Close" button to go on.

 

Are these things related and how do I fix them?