Using Photoshop 6, I've moved from a 2 monitor setup to a single monitor setup, where the window showing effect controls was displaying on the second monitor and everything else in the first monitor. (I no longer have a dual monitor)
Now, on a single monitor, when I click effects under layers with an open project, Photoshop is still thinking there is a second monitor, and I cannot see the effects window that pops up, so I have no control over Photoshop once I click on effects. The only way I can get back control and quit the window (that I cannot see) is to shut down Photoshop through force quit.
How do I reset Photoshop to make it utilize only one screen so that all of the windows within Photoshop will open back up on the single screen?
Well, I've never used two monitors so I can't be sure but.... I really don't think that would be something you would set up in Photoshop. I'm on a Mac and I think to use two monitors I would go to "Displays" in Preferences and tell it to "Detect Displays".
On a PC running Windows, probably right click to Properties > Display Properties > Setting?
If you still have the problem, you might try re-creating Photoshop's preferences but I don't think that should be necessary. Anyway, to re-create the preference files for Photoshop, start the application while holding down Ctrl+Alt+Shift (Windows) or Command+Option+Shift (Mac OS X). Then, click Yes to the message, "Delete the Adobe Photoshop Settings file?"