Hi and welcome to PC Help Forum
You will need to take ownership of the old files before you can transfer them - or have "elevated" Admin rights.
To modify (copy, delete, rename) files or folders you can take Ownership of
(in your Username) and grant yourself Full Control permissions of the files
or folders in question described in the following tutorial. I recommend
doing this for large branches in your directory, like doing this for the
Program Files folder and all folders and files under it so you have Full
Control of all your programs.
Another way to gain access to modify files and folders includes going to the
Start button, typing in Windows Explorer, right-clicking on this and
selecting Run As Administrator. You should then have "elevated privileges"
to do whatever you wish to files in Windows Explorer. There is also a
program called Unlocker that you can use to gain access to modify files and
folders (see link below).
http://www.vistax64.com/tutorials/67717-take-ownership-file.html
http://ccollomb.free.fr/unlocker/