Usually, the services are still kept running up in case you need to do a quick start. If you want to have a scanner for viruses, you don't need a third party app for it. If you have Windows 10, natively Windows Defender is quite a reliable anti-virus. If you are running Mac, it has a couple of layers of protection by default. For manual scans, you should probably install anti-malware software, and you should be good to go. Won't be necessary to install all of the services.