Hi I used a toolnamed "duplicate finder" which find and possibly delete all the duplicate files on your hard disk.On windows folder containing Vista OS
it found 3500 duplicate files on 20000files placed in the folder.I clicked to delete all of them but the sooftware was able to delete only 600 of them.How can I do to delete the rest of them?
Another thing I noticed is that the files replaced by the hotfixes are not deleted but moved somewhere within the main folder of vista os.
Does anyone knows where they are moved?

I would be very careful when deleting those files. The reason you're seeing so many duplicate files is because whenever you install an update vista makes a copy of the files which are going to be updated so that you can uninstall the update later if necessary.

Is there a specific reason why you need to delete duplicate system files?

Clone Remover is very nice software on removal of duplicate files. I’ve been using it for some months and I’m still glad. Now my PC is completely clean.

does "duplicate finder" not compare file version? if it relies just on the name of file and not the file version, i wouldn't trust the program.

As i know Clone Remover relies not only on the name of file but also on the file version. It seems to be an universal program for duplicates.