Robin
1.) The output of mount command you’ve posted looks fine to me. Your partition is mounted read write (you see the rw flag in the line; in case it was only readable this would have been an r instead)
Do all the files and folders on this external drive belong to you? Is it a data vault only, or does the partition contain an operating system also (in this case you need to be way more carefully when taking over the ownership.)
2.) Old folders when created by another old linux system tend to have set different ownership (user-id) to the folders. You can set this straight simply by using the chown command on console with its recursive option. Then the ownership of all the folders and files will be set to the desired user.
sudo chown -R user:group /media/sda2/
Don’t forget to replace user and group both by your actual user name, separated by a colon (e.g. demo:demo ).
But let me emphasise Brians restriction:
IF you are the actual owner of this file and it’s not something shared on a multi-user computer,
Only do this in case you are actualy sure there is nothing stored on it which doesn’t belong to you or is needed to keep its root ownership.
Windows is like a submarine. Open a window and serious problems will start.