Looking through all of the updates, I've found that one of the updates was the
http://support.microsoft.com/kb/933493, which tries to fix some of the performance issues in outlook 2007.
This update is related to this other KB article: http://support.microsoft.com/kb/932086/ that states that the size of the PST file might affect performance... hummm...
My outlook.pst file is 131MB. Googling around found a couple of post that directed me to rename some files from the upgrade/import from Outlook 2003 to 2007.
Shut down Outlook 2007, then I renamed the following files:
"C:\Users\awing\AppData\Local\Microsoft\Outlook\extend.dat" [to extend.old]Open Outlook 2007 back, and now it seems to be working fine again. I have not experienced any more Not Responding hang ups.
"C:\Users\awing\AppData\Local\Microsoft\FORMS\FRMCACHE.dat" [to frmCache.old]