Yes, you can copy all of them.
You can even do the following: copy all you have in partition C to your Ubuntu
partition in a folder in order to preserve all you have under Windows, including
installed programs etc.
Then, when your Windows installation gets messed up in a few months or years
you can just delete everything you have on partition C and copy back your
preserved Windows installation. Such, you will not have to reinstall. But it
occupies space.
I have done this with Windows XP and it worked fine, except for that, at
every startup it showed me some text in Notepad with some info I did not
understand.
So, a Windows installation can be preserved under Linux.
Another funny thing would be to delete your System32 folder in folder Windows
and then try to boot Windows. In this case I also recommend you to have a
preserved System32 folder which you can slam back into the Windows folder.
Another funny thing is starting IE or Notepad in Wine.