One way is using OCR software. The small catch is that IF the program recognizes what's on the file.
There are other programs such as "What the Font" and Adobe Capture which are smartphone apps for the iPhone. Simply take a picture of what's on the screen and it may (or may not) have the result you're looking for.
Now you mentioned .PDF and .TIFF files. Are they flattened ? If the .pdf was created in Illustrator, cross your fingers and hope the fonts haven't been outlined. Otherwise, open it in Photoshop and pray for the same result.