When you got a lot of files which you cannot modify, copy, delete, etc. you must find a way to gain full access to those files. A simple effective method is "use the CMD prompt. Follow the next steps and you get full access:
1. Find the correct "dir" statement to get the filelist you want and redirect the output to a txt file. e.g. DIR /A-D /B > c:\filelist.txt
2. Take ownership of the files listed in c:\filelist.txt with the command: FOR /F %A IN c:\filelist.txt DO TAKEOWN /F %A
3. Take full access to the files with the command: FOR /F %A in c:\filelist.txt ICACLS %A / GRANT Administrator:F
That's it. Now you are owner and have full access.