I copy files from Powerpoint or Excel and then I open a new document in Photoshop and paste the file, but it won't actually place the file until I save it. How can I get it to place the file so I can make changes without saving it first? I can't access any menu items until I save it first.
The place command does require a file on disk.
You can paste an image from the clipboard without going to disk or saving the document.
It sounds like you're still in the place state and have not committed the transform (size, location, rotation, etc.) for the item you just placed. Press the Enter key, or use the checkmark on the options bar to commit the placement.