I'm new to moodle and just started using it because my company has set up a couple courses on it. I have an administrator role and I've been asked to change a student's status to completed. However, I don't even see the list of completions anywhere and don't know how to do this. Is this something I can do in moodle 1.99?
No - the concept of course completion is something in 2.0 and not in 1.9. I am not aware of the facility to do this in 1.9 but hopefully if there is a patch to do this someone who knows about it will be along soon to give more information.