You should not need any software to delete those files.
Check in disk management to see if any of the partitions (it may even be an old SRP) on the HDD in question are marked as "active." If there is an active partition, you can make it inactive using diskpart commands, which will allow you to delete the files from it.
I did have some disks with active partitions on them. I removed all of them so that now there is only 1 active partition which is on my Win 7 boot drive. I then rebooted my machine. I rechecked that there was only one active partition. I was still unable to delete the Windows dir (after which I will kill my prog files also). It came up with a msg saying 'You need permission to perform this action.' 'You require permission from Administrators to make changes to this folder'. I used to just drop to a cmd and use it back with xp and before, but those commands don't work anymore.
So they still won't delete yet.