Taking ownership of file

Hello I had an account on a Windows7 Ultimate but deleted it, before deleting it I moved all the files to a new user. Problem is that I cannot do anything to the file even with full administrative permission I tried taking ownership but that doesn't work. Funny thing I can't open the files but I can delete them. doing some research I was reading into security certificates but I don't understand how it all works.

If anyone could help I would be very grateful.