For the tools to work do the following
1.Deselect the tools. For a MAC press (Command+D) & for Windows (Ctrl+D ).
2.Reset the tools. Right click on the tool icon select Reset Tool.
3.Check that you have the right layer active and that this layer is which is not a layer mask is currently active.
For the unavailable commands
Try to move your to the menu and click there, your commands might be grayed out. If this is the case then go to Imag->Mode menu. make sure that the image color mode and the image color depth are right for the commands that are grayed.