The Problem
There is no built-in protection for your key presses in Windows even if you are entering a password. Malicious programs called keyloggers can record everything you type on a keyboard including your passwords. They can also record your screen, mouse clicks and clipboard contents. Keyloggers can even record a password through clipboard logging if you use copy-paste to enter it. If you use a password manager to protect your passwords, you need protection for your master password against keyloggers.
Is antivirus security enough?
An antivirus solution alone is not sufficient to secure your important passwords. No antivirus is foolproof. There is always a chance to miss some threats.
What about using an ordinary virtual keyboard?
There is no protection in ordinary virtual keyboards against keyloggers. Keyloggers can easily record keystrokes of ordinary virtual keyboards.
The solution
Use a secure virtual keyboard along with an antivirus to enter important passwords. A secure virtual keyboard is a virtual keyboard that protects its keystrokes from keyloggers.