When the image gets open in a new document , press Ctrl+A on that document and then press Ctrl+C then go to the document you want the image in and press Ctrl+V
Regarding your question about restoring default PS settings back , I don't know of any exact way but I think this will work:
create a new user account and in that account , run PS . Now go back to your old account and replace this directory :
C:\Documents and Settings\Old User\Application Data\Adobe\Photoshop
with this one:
C:\Documents and Settings\New User\Application Data\Adobe\Photoshop
both these folders are hidden so you must enable the 'Show hidden file & folders' option first 