Last time I played this game (which was a long time ago) I thought you could break into anything with hit points such as doors, windows, chests, etc.. but I can't figure how to anymore. Any help would be appreciated.

Thank you so much. I have been trying to figure that out for about a month now.

It's also preferable to do so barefisted, or at least with cheap weapons, so you don't break your good ones. If you don't have much strength but do have Dog, you can usually get him to move in and take care of it for you once you start attacking the object.