Hi
I'd leave them there for a week or so just to be sure that you don't have any reason to undo your update or retrieve anything from them, i.e. address books or favorites etc.
Then it's safe to remove them.
You will probably get a message that says you can't delete the Windows.old file when you try.
If you run CCleaner you will see that the file appears, in the lower part of the list under System or Advanced, I don't remember which.
Just check the box and run CCleaner and it will get rid of it.
It may be that the Partition Marker appears there as well but I'm not sure.
Mike