since updating windows 8 to 8.1 I can't access my pictures and some other folders in my documents. what shall I do?

Are you logged in with an administrator account ?
Are you logged in with the same Windows/Hotmail/Outlook account that you were using before updating ?
Did you install Windows 8.1 on top of the old system, on another partition or did you update normally through the Windows Store, etc ?

I had the same problem when I updated to 8.1. It seems that there are folders in the directory that for some reason when you click onthem you get the "access denied" error. I kept on searching and found that windows created additional directories with the same name onthe drive. Those folders I can open. Good luck