Mail Help

Recently I opened my mail and deleted some emails and when I tried deleting one of them the application closed and a message popped up saying it could not be put in the trash.
Now it won't let me open or quit Mail, any suggestions as to what I should do? I just want to quit the application but I try apple q and it doesn't do anything.

Any help would be appreciated.

I don't know the cause of your problem but if Mail is still open and you want to quit it then try pressing the Command Option Esc keys. Now pick Mail from the list and click on the Force Quit button. If that doesn't work then try restarting your computer.