When I try to use the text layer tool, the box to type in shows up but none of the text will. I've tried adjusting the text size, font, color, etc. and nothing will work.
What version of Photoshop are you running? On which Operating System? When you type the characters into your text box in Photoshop and click the Confirm icon or press the Enter on the numeric keypad, is a new text layer created? What's the name of that layer?
This info should be helpful in running down the problem you're having.