Upgrade to latest Coreldraw 2018 and Uninstall CoreldrawX5

Have purchased and installed Coreldraw Upgrade today.

I am trying to uninstall CoreldrawX5 to declutter my laptop.

Uninstall tool is asking me for my serial number for the old program. When I copy that in it says it is incorrect.

I have no other serial number and it is the one I used to install originally.

What to do?