Do not Run Antivirus Manually

Do you open the security suite and execute scans? The default Windows antivirus Microsoft Security Essentials and other such programs think that the system needs it and provides a warning else the computer would be at risk.  

These manuals are not what they are meant to be. If you have a relevant suite then it would do its job in the background without any external help. It would alert when there is any problem.

Manual scans are not necessary

Irrespective of whatever software you use it would always run in the background. Everything that runs on your system is monitored thereby ensuring that no malevolent processes are being executed. Whenever a new file is downloaded or the program is opened it would start its work in order to examine the file and compare it to viruses prior to allowing it to run. If the virus is downloaded the antivirus support software would notice without you having to scan anything. It would deal with the file without manually scanning. This is called real time protection or background scanning or on demand scanning and so on.

The application would check every malware that has arrived. You would not have to click any button as it has already started its work. Normally it runs once a week in the background without interrupting the user. 

When the manual scans should be executed

These scans are useful but it need not be opened regularly. Manual scans are still useful in some cases. When an Antivirus is first installed it would perform a full-system scan right away. This allows ensures that the system is in a clean state and the viruses would not loiter in unopened files on the hard drive. But when you would open the files they would be scanned again. 

Regularly the definition files of antivirus are updated. They contain a list of identified malware and the antivirus compares programs in order to see whether they match or not. There is a possibility that there is a virus in the executable file on your hard drive and the security program missed during the first scan manually. In case a virus definition has been added it would catch the dormant virus when the scan is performed. If you run the file which has the virus then it would be caught. 

At a time run a single antivirus support as implementing multiple ones can cause issues problems with your computer. In case you want to scan with a second application then do a manual scan with the second one instead of the background feature of scanning. 

Background Protection is preferable

In some programs background scanning can be disabled and perform manual ones only. A manual scan is like telling a security guard to search each and every part of the house for intruders. That way it is better to guard the house entrance so that the threats can be caught before even entering the house. When the program can hide itself as well as prevent the antivirus program, Windows Task Manager from running. This is called root kit.

The malware can be detected before the virus can run on your PC. So make use of automatic background scanning and not manual scans. Make use of automatic scans as it provides maximum protection.