Can't change name of user folder in c:drive that was once locked.

Hey, I'm new here and "some" of what's been said covered part of my problem, but...anyway, I figured out how to remove the lock from a user profile folder that was put in my computer under another name then mine before I got this comp. It had the lock on it at the time but I removed it today. I then tried to rename the folder but it won't let me...I can open it and it shows everything I've downloaded, etc, but it's under someone else name and it bugs me. My name is set as the owner and administrator and I am "supposedly" the primary user, but, and this is after I changed the other name to mine in the registry, when I go to the stupid users folder it still shows the main user as this other person under his name, not mine. I can't think of what else to do to do to change the name. I feel like I've tried everything. I would try to delete the folder but I'm afraid I'll lose everything in it since it's all under his name and not mine. How can I change the folder name?