Mac Mail will 'open' but the window does not appear. I can quit it as well. I have rebooted etc. but nothing works. This is out of the blue, it worked yesterday and have not had any recent updates (10.6.8)

Hi-

Mac mail has been giving be troubles recently. About two weeks ago when I started a new message, for some random reason, the send button etc. on the new message window were gone- so I have to go to the menu to send it. Oddly, this doesn't happen when I am replying to a message. Then, this morning, I opened mac mail and the program launched, it even shows that I have messages (so it is obviously loading) but the window is not there. It quits normally as well. I have rebooted, etc. with no luck. I have not done any updates or changed anything on my computer either. So, everything seems fine, except for that there is no actual window. Odd