Alt-tab crashes are a separate issue, unfortunately. To get your game to launch in a window, you'll first need to start up the game, and click on the "Options" button on the Main Menu. On the Options screen, click on the "Video" tab, and then click on the "Use Fullscreen" checkbox so that it no longer has a checkmark in it. Then click on the main menu; a message should pop up saying that you'll need to restart the game. When you close the game and launch it again, it should be running in a window.