Fix Fault Ie7

I just started to see these scritp errors and can't fine any help getting rid of them? I open my Yahoo Messenger and sign in. No problem. I double click on a name to send a message and the IM b ... more

When I try to open a pdf link on the internet a new browser opens and then both browsers close.

I can use IE 7 to view most websites but can't access hotmail or sites to purchase items. It says that I've lost my internet connection when I try - bit I can view other sites with no problem. I'm usi ... more

When I try to make a payment on a web site all goes well until I click on 'submit', then a Windows box pops up saying that my credit card number is invalid. It's not and until a few days ago I had no ... more

How can I stop this appearing on sites visited where I want to look up information? I am using Win XP 2P and have IE7 and a Dell Dimension 8300