When I got my new PC with Win7 in October it was running Internet Explorer 8 which ran aweful, the current version is IE9 which should work fine
I'm pretty sure you would of had nags to update and recently there was a browser choice appear on my desktop
The other thing is you run Norton's internet software that can slow things down, I've never used it but my sister is always complaining about hers
if you play farmville and use the snag bars they kill Internet Explorer!
Chrome and Firefox are a lot faster than IE9, it doesn't hurt to try a different one, just don't make them the default brower until your sure you want to change, personally I stick with IE9 but I do have Firefox which is better for web site stuff
Is it just the internet that doesn't respond? If its doing it with everything, ie desktop, downloaded games etc it could be the mouse click delay needs adjusting