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I can't delete a file - even when using unlocker
I tried all the tools from the question How do I delete a 'locked' file?, and they didn't help.
All the software suggested to download attempted to unlock my file, but they all failed. Additionally, booting into safe mode still didn't solve my problem.
When I try to delete the file (an ISO image that I created of the Windows 8 Install Checker), I get this error:

I obviously can't end System.exe, that'd crash my computer. I've been trying to remove it daily, and it won't let me delete it, even right after a restart.
It's stored on my desktop, and I can't move it, because I get that error.