Deleting old steam folder after moving installation to another place

[ANeonSkinJoke]

Hello,

I only recently upgraded from Xbox to PC so I'm kinda new to steam. May this be my excuse for f***king up my folder. So, I at first installed steam into basic c: / programfiles folder but later realized I actually wanted to install it into D: and not program files. To mod skyrim and stuff. So I followed Steam instructions - https://support.steampowered.com/kb_article.php?ref=7418-YUBN-8129 - , deleted files except steamapps and steam.exe and tried to move folder to hard drive D:. But I recieved error message claiming that they couldn't be deleted since "files are opened in another location, please close them to proceed". No they were not, I had closed every folder and running program but still got this message. I tried to uninstall steam from control panel, but that only claimed that "steam has already been removed". So I reinstalled steam into new location, D:, and then uninstalled it to remove install settings and stuff from windows (I'm using 8). Then reinstalled it to this new location in D: and moved steamapps folder (I moved it into desktop and created backups with steam backup tool already) into new Steam folder. I don't know yet if it's working cause Steam is currently updating my games which it says takes another hour. But my actual guestion right now, why do I get this "file is opened in another location and cannot be removed. Close other locations to continue*" error message when no other locations, apps of whatever is open and how can I delete this dead steam folder from program files? I don't know if it's actually hurting but I don't like these zombie folders eating up my hard drive space.

*in case that sounds weird, my OS language is finnish so that's my own translation of the error message.

Thanks for help!