I not sure I understand the question. Are you opening the File menu, but are not able to select any of the commands listed in that menu (New, Open, Browse in Bridge, etc.)? Can you please share a screen shot?
What version of Photoshop are you using and which operating system?
Without a screen shot, we can only guess. If they items are grayed out, then you may be in the middle of a feature you need to exit, such as type, crop, or a filter (to name a few). Exit that feature by accepting it or canceling it and the menu items will be available again. If you don't see it, give us a screen shot or try pressing Escape.