hard drive access

My porsche hard drive now has restricted my access to my backups after my school wiped and reset my Macbook. I can open the backups but after i get to my user folders like Desktop or Downloads all have the red circle and white line and wont let me open it because i dont have permission. I have changed the sharing and permission settings to "read and write" but still it says i have no access. I can drag them to my desktop and open them but i have to download an hours worth of files. Sometimes I cant change the permission to read and write and it just stays as no access. please help me. No matter what i do i cant get rid of the no access sign or get into the folder. I can access folders from after my wipe.