Outlook 2010: Can't open the Outlook window

I have Outlook 2010 x64 on Windows 7 x64. Today when I tried to open Outlook I got

Cannot start Microsoft Outlook. Cannot open the Outlook window.

I rebooted my machine, nope. I tried outlook.exe /resetnavpane and outlook.exe /safe from the Run prompt, no joy. I ran scanpst.exe and did a repair, no go. I went to the Mail control panel and created a completely new profile, still no luck.

I don't believe I've run Outlook for at least a week. I know several critical updates came through this past Tuesday; might one of them be the culprit? If at all possible I'd like to not have to do a restore or reinstall. Please tell me there's another way.

Edit: Should have mentioned, this is a client install for POP only, no Exchange.

Answer

I found the answer, and it's closely related to the resolution of a previous question of mine. Obviously something is not quite right in my Windows 7 install.

Where before the problem was in HKCU\Volatile Environment, and the %APPDATA% was set to, literally, "%APPDATA%", I reread through the post referenced in my previous question, which suggested checking HKCU\Software\Microsoft\Windows\Current Version\Explorer\Shell Folders and HKCU\Software\Microsoft\Windows\Current Version\Explorer\User Shell Folders to see if the AppData key was missing.

I checked HKCU\Software\Microsoft\Windows\Current Version\Explorer\Shell Folders first, and AppData was correctly set. However, when I checked HKCU\Software\Microsoft\Windows\Current Version\Explorer\User Shell Folders, the AppData key was set to "%APDATA%". I changed it to "%USERPROFILE%\AppData\Roaming" and now Outlook is working again.

What tipped me off was context menus were opening to the left, just as in my previous question. I don't know how these things got screwy, but both times it happened after Patch Tuesday. I'd love to know if anyone else has had something like this happen, and why it happens.