Wonderful to see a problem posted in 2011 that STILL does not have any useful answer in 2015 - despite dozens of people posting useless nonsense that COULD NOT be useful to the person who posted the original question (Hint: don't just tell someone to go to their Outbox to delete the messages when they post that they have already gone to the outbox and there are no messages there)
I am facing a slightly different variation of what seems to be the same basic underlying problem.
Windows Live Mail WON'T open except for what is supposed to be the "Send/Receive Progress" box -- which only shows the current task as "Send 2 message(s) using [my default account]" and a status of "0 of 1 tasks have completed successfully" -- it doesn't ever reach the program screen so I can't even try to delete the messages it thinks it is trying to send - and it doesn't time out (despite waiting far longer than the time limit)
All clear as mud to me !