I see that my free avast allows multiple devices but I need to be sure that I can safely Uninstall the free-year-McAfee from my new PC before proceeding.
Implied in your queston was ‘Do I need to uninstall Avast on the old system first before I install new Avast on the new?’
No, you can keep both programs running on old and new systems if you wish.
No need to uninstall Avast from old system.
Strongly recommended to follow Asyn’s advice to remove McAfee completely on your new system for best install experience.
I believe that article should start with the following.
Do NOT Uninstall your existing AV before downloading the Avast Offline installation and the current AV removal tool.
Go off-line uninstall the current AV, run the removal tool if required. Then reboot and install Avast using the off-line installation file you downloaded.
I also believe that page could do with an update, one it refers to avast version 17.x. It also needs more information on Avast Support for XP ending/ended and also needs to refer to the last supported versions for XP/Vista and the requirement for SSE2.
+1
Definitely, things have changed, and updated XP info is required.