You Need Permission to Perform This Action

I'm sure there are other threads about this topic, but most of them are while a user is trying to delete a file or folder. I am simply trying to move two files.

Back story:
I'm having trouble running a Steam game, so I decided to re-install Steam. I moved 'steamapps' to the desktop so I wouldn't have to reinstall my games, and uninstalled and reinstalled it.

Now I'm trying to move 'steamapps' back into the correct place. All of the files moved successfully except for 'sourceinit.gcf' and 'winui.gcf'. It gave me the 'You Need Permission to Perform This Action' pop-up. I am the Administrator, there are no other users.

I've looked up how to fix this problem and most commonly it is suggested that I should give myself ownership of the files through command prompt, which I did. I also looked under the Security tab for both files and the 'steamapps' folder, and I have full permissions.

It might not be that you need ownership of the two files you're trying to move, but rather ownership of (and full permissions to) the folder you're trying to move them into. Have you checked that?

A move command is in fact two commands together.

First it will copy the files from source to target folder. After the successful completion of copy files, it will delete the source files.

You have to find out where you are getting the problem, during copying or during the delete after copy.

Instead of moving the files, try to copy the files first. After successful copying you can delete them later.

Check the ownership permissions of the target folder. If the ownership permissions are with another user like System, take ownership and after copying the files, revert the permissions back to the default owner.