I have the same problem. unwanted periodic pop-up dialog box trying to find the "hpdiags" app in the windows store which I uninstalled months ago. just prior to the pop up looking for the app, you can see a command line window popping up trying to run something (since it disappears quickly, I can only guess it is trying to run "hpdiags". Ever since I uninstalled HPDIAGS this annoying pop up keeps interrupting my work.
I followed the update windows and update HP support app. This did not fix the issue.
This must have been a bug in the way the old hpdiags app installs itself. When it gets uninstalled, it still leaves something in the start-up/ cmd line script or something that triggers its own launch, only to find the app doesn't exist... Is this in the config file? the