I recently upgraded my laptop to Windows 7 with Office 2010. After getting everything setup I was experiencing a problem with Outlook not reopening after I had previously had closed it. I would check the task manager and it would show to instances of Outloo.exe running. I would kill the one with the highest memory usage and Outlook would open. I began disabling and enabling Outlook add-ins until I found that the problem was caused by “OutlookChangeNotifier” which is installed with iTunes. Once that was disabled Outlook opened and closed without any problems.