remove windows folder from old drive
Open a command line as administrator and copy these lines one by one:
Note: replace the folder address to the folder you want to remove
takeown /F "Z:\Program Files" /A /R /D Y
icacls "Z:\Program Files" /T /grant administrators:F
rd /s /q "Z:\Program Files"
if it didn't delete the folder fully do the steps again from top to buttom once more