While I can not substitute for their support, I would look around the app's settings for boot time scan and turn that off if it always runs at startup.
Otherwise if you can't find the setting, uninstall this and select another AV system.
avscan.exe always running in my laptop every the first time my laptop connected to internet. So how can i prevent that to not happen again? because it is so annoying to must wait the scan is done before i can really using my laptop.