Show User Name in Comment Box

Hi,
I have a workbook in which i want to give it User Name & Password only for 2 persons. Except these 2 users if anyone will open it will ask maximum 3 times to put User Name & Password. If 3 times the input will got wrong then person can only see the files and not get any access to edit / change. Just like read only. The file will not saved with the data feeder by that user.
2nd: When the 2 accessed users will edit any data in this Sheet1 the name of the user will mention in Comment box so what anyone can found who was edited the cell. Thanks.

Hi All,Please help me out if it is possible in Userform.