The reason that WPS was conflicting with Avast is because an older free version (10.1.0.5671) was installed that I had downloaded from the Kingsoft Store website several months ago.
After AntiVirusASeT mentioned that the latest free version was 10.2.0.5820, I went back to the Kingsoft Store website but the latest version is not yet listed. I did a Google search and found it in another section of the Kingsoft website.
I installed version 10.2.0.5820 and it runs like a dream without Avast blocking it.
Thanks for everyone's support in resolving this issue.