Question: If a student is allowed to access something like Excel while taking an exam in Exam.net can they then access any Excel file on the computer? Or can you make it so that only a new file can be accessed? If they can access any file, can you see in the cheat log what file they opened?

Answer: No, it is not possible to restrict the student only to access a specific "Excel" file, and if you turn down the cheat protection (making it possible for the student to leave the exam to go to "Excel") you will not be informed what the student did outside of the exam, you will only know how long he or she was away for.