Can't add mp4 file to itunes. Plays in quicktime but not in itunes. windows xp

I have been trying to add mp4 files to iTunes 12.1.3.6 on a windows xp machine. The files never add. this machine is using quicktime 7.6(472)

on the xp machine

• they open in quicktime with a Right click | open with quicktime but not with Right click | open with ITunes.
• I have uninstalled quicktime and iTunes and reinstalled both. ITunes first if that makes a difference.
• The files are not read only
• I am using an administrator account
• they are not showing up in home videos or other type of video
• I have used these same files on another machine using iTunes with no issue. However it is Windows 7, iTunes 12.5 etc

Any suggestions?!? I am baffled.