Please attempt one of the following solutions.

1. Press Ctrl + Alt + Delete
2. Process tab
3. Click Memory
4. click Outlook.exe
5. End Process


In Outlook 2007

a. Select Tools.
b. Click Trust Center.
c. Click Add-ins.
d. Click COM add-ins.
e. Click Go > Deselect the add-ins you suspect might be keeping Outlook open
f. Close dialog.

Hope this helps.

Mophead