Probably some program either running in the background or a program in the background that failed to complete.
If you have not installed anything recently hard to pin down. If something was installed recently or updated remove or try a restore to a date before this started.
Obviously if everything is running fine more a PITA than a problem
Thanks. I've stalled quite a lot recently as it's a new laptop. I've also done a lot of uninstalling too (after discovering loads of software advertised as FREE when they're not!). I can't pinpoint the date this started so restoring back to before then won't be possible. I guess if there's no solution, then, (hard to believe) I will have to put up with it! Cheers.
CCleaner also has an interface that lets you decide what starts at boot.
You can disable things easily and re-enable them quickly as well.
If you can find what is trying to start you can just stop it from trying to load.
You can avoid issues like this in the future by running another free program called Revo Uninstaller.
It looks for all the leftover stuff when it does the uninstall.
"Mindspark Toolbar Platform" + "gb-installer-core" + "Pokki" are all Adware/PUP
First make a restore point !
Try to locate and un-install anything related to the above "programs" via Control Panel-Programs (and Features).
After that do a full scan with Malwarebytes Anti-Malware and let it remove/quarantine everything it finds.
Report back if you have any problems and if these boxes/windows still appear.