I know this could be a duplicate, but let me explain.
Let's say I want C:\Users\Me to be a link to E:\me. Like the other question says, I tried doing mklink /d C:\Users\Me E:\me. However, I get a "Cannot create file when that file already exists" error. Obviously, the C:\Users\Me folder already exists. But if I try to delete, it just comes back instantly. I tried logging off my account and logging in as the administrator, but I still get that same error.