I was on holiday today but a call from a friend had me in PC repair mode. The problem was Outlook 2007, on a home PC so no Exchange, refusing to start with the message:
"Cannot start MS Office Outlook. Unable to open the Outlook window”
This one was new to me so I ran Office Diagnostics to check the install. That was clean so a bit more research was required to find this simple fix. Just fire up Outlook with the command:
Start > Run > Outlook.exe /resetnavpane
After that Outlook started normally from the icon, back to the holiday!