I think users expect that when they hit the "Check for updates" button, they will get a list of available new versions, and will then be given the possibility to install a new version. Now the updating process just starts immediately.
Also, when the updating was successful, I think a message saying "Updated" would be nice, and it doesn't make sense to check for updates again so the "Check for updates" button should be replaced with a "Close window" button.
I think users expect that when they hit the "Check for updates" button, they will get a list of available new versions, and will then be given the possibility to install a new version. Now the updating process just starts immediately.
Also, when the updating was successful, I think a message saying "Updated" would be nice, and it doesn't make sense to check for updates again so the "Check for updates" button should be replaced with a "Close window" button.