Need To Copy Over 1,000,000 Files With Thousands Of Subdirs.

I have been using a drive (F:\) with Windows XP installed as an external backup. My boot drive is C:. I need to delete XP from (F:\) but have not been able to do so by hand as the system32 folder does not want to delete. On this backup drive and sub directory (F:\Backup) I have over 1,000,000 files with tens of thousands of sub directories. I want to copy all the files and sub directories from (F:\) over to another drive and sub directory (G:\FromDriveF).

I can only use the backup drive now (F:\) with windows installed by only using an external drive bay because the backup drive (F:\) with Windows installed kicks out an error while preventing drive C from booting up.

I tried a fast copy freeware program but the program indicated it would take days to complete the copy. Many files and directories have already been copied but I am not sure the copies match the source drive.

Questions: Is the old dos copy command faster then Windows copy? Is there a dos command that will copy only changed files? Is there a freeware program that will copy the source drive content without taking days to do so?

Thank you in advance for your reply.