How to delete previous windows file.

I re-installed Windows 7 from (C: ) to (D: ) and it had left program files, program files (x86), and windows. I was able to find a command prompt that changed the ownership of the files and allowed me to delete the proram files but it will not work on the windows folder and I can't find any solution.

copy anything important you have from it & format that drive completely?

I know! Press F8 when PC startup, Enter the Safe-mode ,then delete the C:\ windows folder like eating a pie.