>On my Win7 machine IE10 was taking 10 - 20 seconds to load the first page when IE was first opened. This is caused by Internet Options...Connections...LAN Settings...Automatically detect settings being enabled (checked).
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>I turn this off with every computer with every version of IE I've ever used. So, probably the installation of IE10 (automatic upgrade from IE9) turned that setting back on. Just a heads-up if you're seeing this problem.

One reason I've turned off automatic updates of everything Microsoft I could. Somehow they always reset some settings back to default, and on every reinstall of any of the windowses, the hard part is always remembering (and then finding) where the defaults are wrong and a setting needs to be changed.

The one place where it's the worst is skype - affects your pocket: see here.