Outlook 2007 Email Attachment Issue

Hi to all.
I'm running Outlook 2007 on a fast laptop, Win XP Pro, SP3, all Outlook updates current.
Everything is very fast...until I attach a file to an outgoing email. After hitting "Attach File", I choose a directory. On the 2nd selection, a folder or file in that directory, the computer hangs up for about a full minute, then resumes. After that, I can move around any directories & folders lighting fast...attach files over & over, until I close down Outlook. When I open it again, the same thing happens the first time I try to attach a file to an outgoing email.
ALL other functions work perfectly all of the time.
I opened up the Task Mgr during this event, and the CPU Usage goes to 0%. The Outlook INBOX, Outlook New Message, and an additional INBOX appear in the Processes, and all are "Not Responding". After the minute hang-up, all processes revert to normal.
I have quit Skype as well as uncheck all ADD-INS in the Manage Add-Ins. I am NOT on a network or using Exchange.
The size or contents of the folder or file does not matter.

Any help/thoughts are appreciated.