Here are some key board short cuts for photoshop CS3 should work in most versions.
short cut 1
- as soon as you click photoshop icon to start it quickly hold down keys [ Control/Shift/Alt ] you get a pop up box asking to delete photoshop setting you go yes, [ what this does it resets photo shop files to default start up/resets all tool defaults.
Good for starting a new job
Short cut 2
- Now to undo say your last ten movements in photshop use keys together [ Control/Alt / Z] What this does is undo around the last ten or more movement you made on that job, just keep hitting those keys till you back to where you want to start again.