Photoshop :: Screen With No Controls

An image is on the monitor and I inadvertently must hit a command or key and the screen goes into a maximized mode. My image is still on the screen but everything else is gone. I cannot minimize since those buttons are gone. I right click or left click on the mouse and nothing happens. I cannot even shut down the computer since those controls are gone. It is necessary for me to turn off the computer using the off/on button. What I get on my monitor is the image that I was working on and a neutral background that covers the entire monitor.

I am running Photoshop 6 and XP.