A standard user cannot access the /root directory, only the root user can do
so. To access it, you'll need to use either sudo or su.
And standard users cannot access some mounted devices and partitions so you
may have to access it with sudo or su.
You could also use the chown command so that your user can edit the partition
or device without root access. Make sure that the perm status of the files in
said partition are not important...
$ lsblk
(It'll list the partitions, devices, and mount points)
$ sudo chown -R (Your user-name) (Mount point of partition)
And as for sda5, perhaps you should try to remove it with GParted? Perhaps
you can't remove it because it's mounted?