upgrading to zorin 8.1 from 6

Hello,
I want to upgrade the zorin os
I tried to follow these instructions: http://zorin-os.com/upgradeguide.html
But I am having problem at the step, to delete the partitions.
Partition ext4 is 7.02 gb and free space 742 (don't ask me why so little free space, I don't know with what).
When I try to delete this partition it say
"unable to delete"
"Please unmount any logical partitions having a number higher than 5"
Partition linux-swap 1.93 gb
The delete option is not activated.

What to do?

Please explain it as easier as possible, I don have any experience with linux.

Hi,

you cannot delete an active (a partition that is currently being used by the system) mounted partition!, .

Pleae see the partition guide for more info about partitioning:

viewtopic.php?f=6&t=2601

See also:

viewtopic.php?f=6&t=4848

Let us know if it helps.