Default [Q] Help with Razr Maxx unroot

I have a rooted razr 2.3.6 that I am trying to unroot so I can do the most recent update. I had a friend who helped me with all this stuff, but sadly he passed recently. I know little to nothing about this stuff, and would sure appreciate someone to hold my hand through this. I know I have superuser, and when I try to uninstall with my file manager it won't let me. I know everyone on here seems to use SU, but I'm obviously held up by superuser. Can someone please help this stumbling fool?!!