EverythingIBM was on the right track, and you could have done this without using an Ubuntu boot CD. It's 3am, I'm bored and you've given me an excuse to type on my blues :tongue:, and this way more people might know how to actually resolve this in the future. And yes, Windows Vista / 7 has made this unnecessarily difficult in some silly attempt to protect users from themselves.
1. Forcefully take ownership of the old Windows folder, as well as all sufolders and files. It's pretty easy to do, just takes a few sub menus and few minutes for it to modify all the ACLs. Specifically, once you have found the Security tab, click Advanced, select the Owner tab, click the Edit button, select the new owner in the 'Change owner to' box, put a check in the "Replace owner on subcontainers and objects" box, and click Apply. It should be done in a few minutes.
2. Grant yourself Full Permissions to all subfolders and files: Get back to the Security tab, click the Advanced button, click Change Permissions on the Permissions tab, either select the listed user or group (or add it if necessary), click the Edit button, select Full control, in the Apply To box make sure it says "This folder, subfolders, and files", select Ok, select Apply, and wait a few minutes for the permissions to propagate.
3. Delete away.
I've had to do this a few times when working on friends systems cleaning up old data, so I'm sure it works.