Outlook 2007 - Mail stays in outbox, will not send..

Outlook 2007 mail stays in outbox...
When clicking on the send button, the outgoing mail goes to the "Outbox" and does not send.

Wife is not sure when it started, (at least the last two days or so).

I took the email from the "outbox" and moved it to a different folder, re clicked the send button, and the mail was sent. (this did not work in the "outbox" that's why I moved it)

Any suggestions? Corrupt "Outbox "? Fix?

Sony Vaio/laptop 64bit

 

If Arie's suggestion doesn't fix it you might try uninstalling and reinstalling Office.