Help regarding System32 and ownership, Windows 7 Home Premium

Let's say there's an off chance I might have accidentally took ownership of my entire system32 folder, but so far nothing bad has happened. Am I still screwed? What if I made a backup of my system32 folder except for a few files that refused to copy?

In case you're curious and want to get to the root of the problem, I've been trying to install this: Browsing deviantART logon screen via the replacement of the authui.dll file. After taking ownership multiple times and running those two command lines whose name escapes me for both files it still absolutely refuses to be replaced.

Either A: I drag and drop the new authui.dll into system32 which tells me I need permission, or B: I copy and paste which tells me that it is being used in another file. I was able to do it once somehow and after restarting I found that nothing changed, I couldn't paste in my backup or put in a new-new version either. I also tried inserting the new authui.dll into SysWOW64, which after taking ownership once replaced the old one immediately, still didn't install the new logon screen though, in fact I think it actually looks a bit uglier; the picture is larger and the transparent borders are larger (although I'm pretty sure it was like that after I replaced the System32 one first).

Anyway, I would greatly appreciate if anyone could offer their knowledge to help me. Especially if you could answer why this is happening to begin with.