It seems that recently 2 Windows XP Pro computers in my network have had Office Communicator 2007 R2 break. When you click on the Communicator start menu shortcut, you never see communicator open or show up in the task tray. When you look at task manager during this, communicator.exe shows up for about 1 second then disappears. I've uninstalled and reinstalled. Checked the COM+ and RPC Services. Disabled antivirus and security software. Other XP computers are working properly. Any ideas?