Changing permissions on a folder with subfolder and files that's parent user was removed from another computer?

[tommay]

Changing permissions on a folder with subfolder and files that's parent user was removed from another computer?
The title says it all. I need help with this. I try selecting every file but it does not allow me to 'take ownership.' Can somebody tell me how to take ownership of every file and folder or just remove the permissions from the previous user?

By the way, these folders were backups from my old pc that were moved to an external hdd.

 

[Taffu]

Assuming that you have administrator privileges:
1. Right click the folder in which the files are, and click properties.
2. Go to "Security" tab.
3. Click "Advanced" tab, here you can assign permissions.
4. Go to the "Owner" tab.
5. Click "Edit" and assign your user as the owner.