windows 7 - How to change file permissions when you don't have permission to change file permissions?

I often (like just this morning) have a situation where I need to delete or replace a file that may be located in folders like C:\Windows. When I try to do this I always get access denied. Every resource I can find shows me step by step how to modify the permissions, I already know how to do this. The problem is when I try to modify permissions and it tells me access denied. I don't have permission to modify the permissions! This happens even when I launch Windows Explorer or CMD as Administrator (my account is Admin), and even when I tried using cacls. UAC is at the lowest possible setting so it never bugs me. What's the deal Windows 7? Why can't I own all my files? It's so annoying that sometimes I actually boot Linux to go edit/modify a Windows file! Ok rant over, but can anyone solve this for me?

Answer

Have you tried taking ownership over the file. Instructions for hand right click menu here.