Cannot Rename Folder / Access Is Denied

The rest of the message says "Make sure the disk is not full or write protected and that the file is not in use".In Folder:Properties, the file shows as 'Read Only'. Unticking this box followed by the option to do the same for all folders and subfolders, then using 'Apply' was unsuccessful, as when I tried to rename the folder after doing this,the message reappeared, and the folder was again 'Read only'.As Administrator, my understanding is that I have full permissions under the Security section of Properties, which appears to be the case, as all boxes are ticked.The path is as follows:- C:FOLDER:Sub folder 1Sub..1 cannot be renamed. It contains four additional folders, (each with loads of subfolders),of which 3 can be renamed, whilst the fourth one cannot, with the same "Access denied..." message appearing.