There is NO such thing as a UN-Deletable file. To make it all the easier, I have my C: drive formatted as FAT-32, so I can boot up (Windows XP) with my DOS boot disk and go into C: and do anything I want with any file I want.
* Windows XP will run like a screaming demon, on a FAT-32 formatted HD.
Or with an NTFS drive, I still boot up with my DOS Utilities disk and run NTFS4DOS which opens up an NTFS drive for access from a DOS prompt. Again, I can then go into C: and do anything I want with any file or folder I want.
I can even delete the Windows password with another app on my Util's disk.
To delete a .dll
file, just rename the file to something like filename.ddd
and reboot and the file will not load and will be fully deletable.
I'm getting too old and cranky to put up with some OS telling me I don't have permission to do something with my own computer.
That's just NOT going to happen!!!!
When I set up any PC, with Vista, Win-7 or now with Win-8, I run the registry Script "Grant Full Admin Control.reg" and with that loaded, I can right click on any file or folder (except the root directory itself) and make myself the OWNER of that file or folder. When I OWN it, I can do what I want with it.
I also turn off UAC and UN-Hide hidden files.
For us who like to mess around with our personal computers, being in FULL CONTROL of everything on that computer is an absolute MUST.