IE7 locks up after install

I have been installing IE7 on my machines and had great luck until today. I installed it and rebooted. When I tried to load it, the program would open, but it would just sit there with ‘connecting…’ on the tab. I let it run for several minutes and nothing. Then it would let me exit the program without killing the process from task manager. When I uninstalled it back to IE6 it worked fine. I tried reinstalling IE7 and the same thing. So I uninstalled it and said the heck with this, but it now has my curiosity. Any idea what would be causing thing?

Thanks

Bob