Smtp4dev block my localhost

Oct 5, 2014 at 1:25 PM
I run the Smtp4dev.exe in my pc, and after that I try to enter my localhost,
I arrived to 404 error,
and when I checked my IIS, I saw it;s stopped,
but when I click the play button I got an error that some program is using the file..

how can I release the file so I can run my localhost?