Since you mention the Command key, I deduce you're on a Mac.
Try calling up the Display Preferences and clicking on the "Detect Displays" button. If it doesn't work, you've lost nothing.
and now even after i reset settings it still has the window missing sometimes... i have not connected the monitor for 2 days....
I don't know the procedure for handling dual monitors/projectors etc with a Mac, but with Win 7 it is doable even if you can't see anything on the screen. Try toggling through the options to restore the single monitor status. If you can actually see Photoshop, then just reset your Workspace. I can't see what version of photoshop you are using, but Workspaces will be on the options bar
there is another great trick for windows, I assume there is something Similar on mac. I had an issue with AfterEffects this morning and had to do it. I have 2 different dual monitor setups with the same laptop. One at home, and one at work. I am guessing that's what caused the issue.
I tried saving two different workspaces, but that didn't work.
My entire second monitor was completely offscreen.
The trick is this:
Turn OFF one of the menus that isn't showing up, then turn it on. That will activate it, but won't move it.
Now hit Alt+Space. This brings up a menu (which you won't be able to see) and you then hit M.
Now click down the mouse and hold it, as soon as you move your mouse the whole thing will snap into your window.
Alternatively, you can use the keyboard arrows to move that.
You can try this process on a window you can see so you know what is happening.
I don't use mac enough to know those types of tricks, but I'm betting there is something similar.
Adobe Should always check to see if the bounds of any window are offscreen, but they don't. On a Mac, I'm also guessing the window could be on a different virtual desktop as well. I went over to a coworker's computer and he had like 20 different desktops for some reason (I don't think he knew how to use them)