iTunes, on my PC, is responding very slowly.

I just updated downloaded and installed iTunes 11.0.1 on my Windows XP professional PC and all seems OK until I try to access iTunes Store or attempt to turn on Home Sharing or try to do anything where iTunes has to connect to Apple. It takes forever to respond to a mouse click and then all you see is the candy cane line which never stops even after 30 minutes. Has anyone experienced this? I have uninstalled and re-installed and that does not appear to clear up the problem. Simultaneous attempts to access internet web pages appear to work fine, so the problem is not with the internet connection.